36 changed files with 4277 additions and 50 deletions
--- a/SmallSoftwareProject/SmallSoftwareBusinessLogic/Implementations/ManufacturerBusinessLogicContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareBusinessLogic/Implementations/ManufacturerBusinessLogicContract.cs
@@ -0,0 +1,68 @@
+using SmallSoftwareContracts.BusinessLogicsContracts;
+using SmallSoftwareContracts.DataModels;
+using SmallSoftwareContracts.StoragesContracts;
+using Microsoft.Extensions.Logging;
+using SmallSoftwareContracts.Exceptions;
+using SmallSoftwareContracts.Extensions;
+using System.Text.Json;
+
+namespace SmallSoftwareBusinessLogic.Implementations;
+
+internal class ManufacturerBusinessLogicContract(IManufacturerStorageContract
+manufacturerStorageContract, ILogger logger) : IManufacturerBusinessLogicContract
+{
+    private readonly ILogger _logger = logger;
+    private readonly IManufacturerStorageContract _manufacturerStorageContract
+    = manufacturerStorageContract;
+    public List<ManufacturerDataModel> GetAllManufacturers()
+    {
+        _logger.LogInformation("GetAllManufacturers");
+        return _manufacturerStorageContract.GetList() ?? throw new
+        NullListException();
+    }
+    public ManufacturerDataModel GetManufacturerByData(string data)
+    {
+        _logger.LogInformation("Get element by data: {data}", data);
+        if (data.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(data));
+        }
+        if (data.IsGuid())
+        {
+            return _manufacturerStorageContract.GetElementById(data) ??
+            throw new ElementNotFoundException(data);
+        }
+        return _manufacturerStorageContract.GetElementByName(data) ??
+        _manufacturerStorageContract.GetElementByOldName(data) ??
+        throw new ElementNotFoundException(data);
+    }
+    public void InsertManufacturer(ManufacturerDataModel manufacturerDataModel)
+    {
+        _logger.LogInformation("New data: {json}",
+        JsonSerializer.Serialize(manufacturerDataModel));
+        ArgumentNullException.ThrowIfNull(manufacturerDataModel);
+        manufacturerDataModel.Validate();
+        _manufacturerStorageContract.AddElement(manufacturerDataModel); 
+    }
+    public void UpdateManufacturer(ManufacturerDataModel manufacturerDataModel)
+    {
+        _logger.LogInformation("Update data: {json}",
+        JsonSerializer.Serialize(manufacturerDataModel));
+        ArgumentNullException.ThrowIfNull(manufacturerDataModel);
+        manufacturerDataModel.Validate();
+        _manufacturerStorageContract.UpdElement(manufacturerDataModel);
+    }
+    public void DeleteManufacturer(string id)
+    {
+        _logger.LogInformation("Delete by id: {id}", id);
+        if (id.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(id));
+        }
+        if (!id.IsGuid())
+        {
+            throw new ValidationException("Id is not a unique identifier");
+        }
+        _manufacturerStorageContract.DelElement(id);
+    }
+}
--- a/SmallSoftwareProject/SmallSoftwareBusinessLogic/Implementations/PostBusinessLogicContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareBusinessLogic/Implementations/PostBusinessLogicContract.cs
@@ -0,0 +1,102 @@
+using Microsoft.Extensions.Logging;
+using SmallSoftwareContracts.BusinessLogicsContracts;
+using SmallSoftwareContracts.DataModels;
+using SmallSoftwareContracts.Enums;
+using SmallSoftwareContracts.Exceptions;
+using SmallSoftwareContracts.Extensions;
+using SmallSoftwareContracts.StoragesContracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Text.Json;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareBusinessLogic.Implementations;
+
+internal class PostBusinessLogicContract(IPostStorageContract
+postStorageContract, ILogger logger) : IPostBusinessLogicContract
+{
+    private readonly ILogger _logger = logger;
+    private readonly IPostStorageContract _postStorageContract =
+    postStorageContract;
+    public List<PostDataModel> GetAllPosts(bool onlyActive = true)
+    {
+        _logger.LogInformation("GetAllPosts params: {onlyActive}",
+        onlyActive);
+        return _postStorageContract.GetList(onlyActive) ?? throw new
+        NullListException();
+    }
+    public List<PostDataModel> GetAllDataOfPost(string postId)
+    {
+        _logger.LogInformation("GetAllDataOfPost for {postId}", postId);
+        if (postId.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(postId));
+        }
+        if (!postId.IsGuid())
+        {
+            throw new ValidationException("The value in the field postId is not a unique identifier."); 
+        }
+        return _postStorageContract.GetPostWithHistory(postId) ?? throw new
+        NullListException();
+    }
+    public PostDataModel GetPostByData(string data)
+    {
+        _logger.LogInformation("Get element by data: {data}", data);
+        if (data.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(data));
+        }
+        if (data.IsGuid())
+        {
+            return _postStorageContract.GetElementById(data) ?? throw new
+            ElementNotFoundException(data);
+        }
+        return _postStorageContract.GetElementByName(data) ?? throw new
+        ElementNotFoundException(data);
+    }
+    public void InsertPost(PostDataModel postDataModel)
+    {
+        _logger.LogInformation("New data: {json}",
+        JsonSerializer.Serialize(postDataModel));
+        ArgumentNullException.ThrowIfNull(postDataModel);
+        postDataModel.Validate();
+        _postStorageContract.AddElement(postDataModel);
+    }
+    public void UpdatePost(PostDataModel postDataModel)
+    {
+        _logger.LogInformation("Update data: {json}",
+        JsonSerializer.Serialize(postDataModel));
+        ArgumentNullException.ThrowIfNull(postDataModel);
+        postDataModel.Validate();
+        _postStorageContract.UpdElement(postDataModel);
+    }
+    public void DeletePost(string id)
+    {
+        _logger.LogInformation("Delete by id: {id}", id);
+        if (id.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(id));
+        }
+        if (!id.IsGuid())
+        {
+            throw new ValidationException("Id is not a unique identifier");
+        }
+        _postStorageContract.DelElement(id);
+    }
+    public void RestorePost(string id)
+    {
+        _logger.LogInformation("Restore by id: {id}", id);
+        if (id.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(id));
+        }
+        if (!id.IsGuid())
+        { 
+        throw new ValidationException("Id is not a unique identifier");
+        }
+        _postStorageContract.ResElement(id);
+    }
+}
+
--- a/SmallSoftwareProject/SmallSoftwareBusinessLogic/Implementations/RequestBusinessLogicContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareBusinessLogic/Implementations/RequestBusinessLogicContract.cs
@@ -0,0 +1,108 @@
+using Microsoft.Extensions.Logging;
+using SmallSoftwareContracts.BusinessLogicsContracts;
+using SmallSoftwareContracts.DataModels;
+using SmallSoftwareContracts.Exceptions;
+using SmallSoftwareContracts.Extensions;
+using SmallSoftwareContracts.StoragesContracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Text.Json;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareBusinessLogic.Implementations;
+
+internal class RequestBusinessLogicContract(IRequestStorageContract requestStorageContract, ILogger logger) : IRequestBusinessLogicContract
+{
+    private readonly ILogger _logger = logger;
+    private readonly IRequestStorageContract _requestStorageContract =
+    requestStorageContract;
+    public List<RequestDataModel> GetAllRequestsByPeriod(DateTime fromDate, DateTime toDate)
+    {
+        _logger.LogInformation("GetAllRequests params: {fromDate}, {toDate}", fromDate, toDate);
+        if (fromDate.IsDateNotOlder(toDate))
+        {
+            throw new IncorrectDatesException(fromDate, toDate);
+        }
+        return _requestStorageContract.GetList(fromDate, toDate) ?? throw new NullListException();
+
+    }
+    public List<RequestDataModel> GetAllRequestsByWorkerByPeriod(string workerId, DateTime fromDate, DateTime toDate)
+    {
+        _logger.LogInformation("GetAllRequests params: {workerId}, {fromDate}, { toDate} ", workerId, fromDate, toDate);
+        if (fromDate.IsDateNotOlder(toDate))
+        {
+            throw new IncorrectDatesException(fromDate, toDate);
+        }
+        if (workerId.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(workerId));
+        }
+        if (!workerId.IsGuid())
+        {
+            throw new ValidationException("The value in the field workerId is not a unique identifier.");
+        }
+        return _requestStorageContract.GetList(fromDate, toDate, workerId:
+        workerId) ?? throw new NullListException();
+    }
+
+    public List<RequestDataModel> GetAllRequestsBySoftwareByPeriod(string softwareId, DateTime fromDate, DateTime toDate)
+    {
+        _logger.LogInformation("GetAllRequests params: {softwareId}, {fromDate}, { toDate} ", softwareId, fromDate, toDate);
+        if (fromDate.IsDateNotOlder(toDate))
+        {
+            throw new IncorrectDatesException(fromDate, toDate);
+        }
+        if (softwareId.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(softwareId));
+        }
+        if (!softwareId.IsGuid())
+        {
+            throw new ValidationException("The value in the field  softwareId is not a unique identifier.");
+        }
+        return _requestStorageContract.GetList(fromDate, toDate, softwareId:
+        softwareId) ?? throw new NullListException();
+    }
+
+    public RequestDataModel GetRequestByData(string data)
+    {
+        _logger.LogInformation("Get element by data: {data}", data);
+        if (data.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(data));
+        }
+        if (!data.IsGuid())
+        {
+            throw new ValidationException("Id is not a unique identifier");
+        }
+        return _requestStorageContract.GetElementById(data) ?? throw new ElementNotFoundException(data);
+
+    }
+    public void InsertRequest(RequestDataModel requestDataModel)
+    {
+        _logger.LogInformation("New data: {json}",
+    JsonSerializer.Serialize(requestDataModel));
+        ArgumentNullException.ThrowIfNull(requestDataModel);
+        requestDataModel.Validate();
+        _requestStorageContract.AddElement(requestDataModel);
+
+    }
+    public void CancelRequest(string id)
+    {
+        _logger.LogInformation("Cancel by id: {id}", id);
+        if (id.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(id));
+        }
+        if (!id.IsGuid())
+        {
+            throw new ValidationException("Id is not a unique identifier");
+        }
+        _requestStorageContract.DelElement(id);
+
+    }
+
+
+}
--- a/SmallSoftwareProject/SmallSoftwareBusinessLogic/Implementations/SalaryBusinessLogicContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareBusinessLogic/Implementations/SalaryBusinessLogicContract.cs
@@ -0,0 +1,79 @@
+using Microsoft.Extensions.Logging;
+using SmallSoftwareContracts.BusinessLogicsContracts;
+using SmallSoftwareContracts.DataModels;
+using SmallSoftwareContracts.Exceptions;
+using SmallSoftwareContracts.Extensions;
+using SmallSoftwareContracts.StoragesContracts;
+namespace SmallSoftwareBusinessLogic.Implementations;
+
+
+internal class SalaryBusinessLogicContract(ISalaryStorageContract salaryStorageContract,
+    IRequestStorageContract requestStorageContract, IPostStorageContract postStorageContract, 
+    IWorkerStorageContract workerStorageContract, ILogger logger) : ISalaryBusinessLogicContract
+{
+    private readonly ILogger _logger = logger;
+    private readonly ISalaryStorageContract _salaryStorageContract =
+    salaryStorageContract;
+    private readonly IRequestStorageContract _requestStorageContract =
+    requestStorageContract;
+    private readonly IPostStorageContract _postStorageContract =
+    postStorageContract;
+    private readonly IWorkerStorageContract _workerStorageContract =
+    workerStorageContract;
+    public List<SalaryDataModel> GetAllSalariesByPeriod(DateTime fromDate,
+    DateTime toDate)
+    {
+        _logger.LogInformation("GetAllSalaries params: {fromDate}, {toDate}",
+        fromDate, toDate);
+        if (fromDate.IsDateNotOlder(toDate))
+        {
+            throw new IncorrectDatesException(fromDate, toDate);
+        }
+        return _salaryStorageContract.GetList(fromDate, toDate) ?? throw new
+        NullListException();
+    }
+    public List<SalaryDataModel> GetAllSalariesByPeriodByWorker(DateTime
+    fromDate, DateTime toDate, string workerId)
+    {
+        if (fromDate.IsDateNotOlder(toDate))
+        {
+            throw new IncorrectDatesException(fromDate, toDate);
+        }
+        if (workerId.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(workerId));
+        }
+        if (!workerId.IsGuid())
+        {
+            throw new ValidationException("The value in the field workerId is not a unique identifier.");
+        }
+        _logger.LogInformation("GetAllSalaries params: {fromDate}, {toDate}, { workerId} ", fromDate, toDate, workerId);
+        return _salaryStorageContract.GetList(fromDate, toDate, workerId) ??
+        throw new NullListException();
+    }
+
+
+    public void CalculateSalaryByMonth(DateTime date)
+    {
+        _logger.LogInformation("CalculateSalaryByMounth: {date}", date);
+        var startDate = new DateTime(date.Year, date.Month, 1);
+        var finishDate = new DateTime(date.Year, date.Month,
+        DateTime.DaysInMonth(date.Year, date.Month));
+        var workers = _workerStorageContract.GetList() ?? throw new
+        NullListException();
+        foreach (var worker in workers)
+        {
+            var requests = _requestStorageContract.GetList(startDate,
+            finishDate, workerId: worker.Id)?.Sum(x => x.Sum) ?? 
+            throw new NullListException();
+            var post = _postStorageContract.GetElementById(worker.PostId)
+            ??
+            throw new NullListException();
+            var salary = post.Salary + requests * 0.1;
+            _logger.LogDebug("The employee {workerId} was paid a salary of { salary} ", worker.Id, salary);
+            _salaryStorageContract.AddElement(new
+            SalaryDataModel(worker.Id, finishDate, salary));
+        }
+    }
+}
+
--- a/SmallSoftwareProject/SmallSoftwareBusinessLogic/Implementations/SoftwareBusinessLogicContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareBusinessLogic/Implementations/SoftwareBusinessLogicContract.cs
@@ -0,0 +1,100 @@
+using Microsoft.Extensions.Logging;
+using SmallSoftwareContracts.BusinessLogicsContracts;
+using SmallSoftwareContracts.DataModels;
+using SmallSoftwareContracts.Enums;
+using SmallSoftwareContracts.Exceptions;
+using SmallSoftwareContracts.Extensions;
+using SmallSoftwareContracts.StoragesContracts;
+using System.Text.Json;
+
+namespace SmallSoftwareBusinessLogic.Implementations;
+
+internal class SoftwareBusinessLogicContract(ISoftwareStorageContract
+softwareStorageContract, ILogger logger) : ISoftwareBusinessLogicContract
+{
+    private readonly ILogger _logger = logger;
+    private readonly ISoftwareStorageContract _softwareStorageContract =
+    softwareStorageContract;
+    public List<SoftwareDataModel> GetAllSoftwares(bool onlyActive)
+    {
+    _logger.LogInformation("GetAllSoftwares params: {onlyActive}", onlyActive);
+    return _softwareStorageContract.GetList(onlyActive) ?? throw new
+    NullListException(); 
+    }
+    public List<SoftwareDataModel> GetAllSoftwaresByManufacturer(string
+    manufacturerId, bool onlyActive = true)
+    {
+    if (manufacturerId.IsEmpty())
+    {
+        throw new ArgumentNullException(nameof(manufacturerId));
+    }
+    if (!manufacturerId.IsGuid())
+    {
+        throw new ValidationException("The value in the field manufacturerId is not a unique identifier.");
+    }
+    _logger.LogInformation("GetAllSoftwares params: {manufacturerId}, { onlyActive} ", manufacturerId, onlyActive);
+    return _softwareStorageContract.GetList(onlyActive, manufacturerId) ??
+    throw new NullListException();
+    }
+    public List<SoftwareHistoryDataModel> GetSoftwareHistoryBySoftware(string softwareId)
+    {
+    _logger.LogInformation("GetSoftwareHistoryBySoftware for {softwareId}",  softwareId);
+        if (softwareId.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(softwareId));
+        }
+        if (!softwareId.IsGuid())
+        {
+            throw new ValidationException("The value in the field softwareId is not a unique identifier."); 
+        }
+        return _softwareStorageContract.GetHistoryBySoftwareId(softwareId) ??
+        throw new NullListException();
+
+    }
+    public SoftwareDataModel GetSoftwareByData(string data)
+    {
+        _logger.LogInformation("Get element by data: {data}", data);
+        if (data.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(data));
+        }
+        if (data.IsGuid())
+        {
+            return _softwareStorageContract.GetElementById(data) ?? throw
+            new ElementNotFoundException(data);
+        }
+        return _softwareStorageContract.GetElementByName(data) ?? throw new
+        ElementNotFoundException(data);
+    }
+    public void InsertSoftware(SoftwareDataModel softwareDataModel)
+    { 
+        _logger.LogInformation("New data: {json}",
+        JsonSerializer.Serialize(softwareDataModel));
+        ArgumentNullException.ThrowIfNull(softwareDataModel);
+        softwareDataModel.Validate();
+        _softwareStorageContract.AddElement(softwareDataModel); 
+    }
+    public void UpdateSoftware(SoftwareDataModel softwareDataModel)
+    {
+        _logger.LogInformation("Update data: {json}",
+        JsonSerializer.Serialize(softwareDataModel));
+        ArgumentNullException.ThrowIfNull(softwareDataModel);
+        softwareDataModel.Validate();
+        _softwareStorageContract.UpdElement(softwareDataModel);
+
+    }
+    public void DeleteSoftware(string id)
+    {
+        _logger.LogInformation("Delete by id: {id}", id);
+        if (id.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(id));
+        }
+        if (!id.IsGuid())
+        {
+            throw new ValidationException("Id is not a unique identifier");
+        }
+        _softwareStorageContract.DelElement(id);
+    }
+}
+
--- a/SmallSoftwareProject/SmallSoftwareBusinessLogic/Implementations/WorkerBusinessLogicContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareBusinessLogic/Implementations/WorkerBusinessLogicContract.cs
@@ -0,0 +1,110 @@
+using Microsoft.Extensions.Logging;
+using SmallSoftwareContracts.BusinessLogicsContracts;
+using SmallSoftwareContracts.DataModels;
+using SmallSoftwareContracts.Exceptions;
+using SmallSoftwareContracts.Extensions;
+using SmallSoftwareContracts.StoragesContracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Text.Json;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareBusinessLogic.Implementations;
+
+internal class WorkerBusinessLogicContract(IWorkerStorageContract
+workerStorageContract, ILogger logger) : IWorkerBusinessLogicContract
+{
+    private readonly ILogger _logger = logger;
+    private readonly IWorkerStorageContract _workerStorageContract =
+    workerStorageContract;
+    public List<WorkerDataModel> GetAllWorkers(bool onlyActive = true)
+    {
+        _logger.LogInformation("GetAllWorkers params: {onlyActive}",
+        onlyActive);
+        return _workerStorageContract.GetList(onlyActive) ?? throw new
+        NullListException();
+    }
+    public List<WorkerDataModel> GetAllWorkersByPost(string postId, bool
+    onlyActive = true)
+    {
+        _logger.LogInformation("GetAllWorkers params: {postId}, { onlyActive},", postId, onlyActive);
+    if (postId.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(postId));
+        }
+        if (!postId.IsGuid())
+        {
+            throw new ValidationException("The value in the field postId is not a unique identifier.");
+        } 
+    return _workerStorageContract.GetList(onlyActive, postId) ?? throw
+    new NullListException();
+    }
+    public List<WorkerDataModel> GetAllWorkersByBirthDate(DateTime fromDate,
+    DateTime toDate, bool onlyActive = true)
+    {
+        _logger.LogInformation("GetAllWorkers params: {onlyActive},  { fromDate}, { toDate} ", onlyActive, fromDate, toDate);
+    if (fromDate.IsDateNotOlder(toDate))
+        {
+            throw new IncorrectDatesException(fromDate, toDate);
+        }
+        return _workerStorageContract.GetList(onlyActive, fromBirthDate:
+        fromDate, toBirthDate: toDate) ?? throw new NullListException();
+    }
+    public List<WorkerDataModel> GetAllWorkersByEmploymentDate(DateTime
+    fromDate, DateTime toDate, bool onlyActive = true)
+    {
+        _logger.LogInformation("GetAllWorkers params: {onlyActive}, { fromDate}, { toDate} ", onlyActive, fromDate, toDate);
+    if (fromDate.IsDateNotOlder(toDate))
+        {
+            throw new IncorrectDatesException(fromDate, toDate);
+        }
+        return _workerStorageContract.GetList(onlyActive, fromEmploymentDate:
+        fromDate, toEmploymentDate: toDate) ?? throw new NullListException();
+    }
+    public WorkerDataModel GetWorkerByData(string data)
+    {
+        _logger.LogInformation("Get element by data: {data}", data);
+        if (data.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(data));
+        }
+        if (data.IsGuid())
+        {
+            return _workerStorageContract.GetElementById(data) ?? throw
+            new ElementNotFoundException(data);
+        }
+        return _workerStorageContract.GetElementByFIO(data) ?? throw new
+        ElementNotFoundException(data);
+    }
+    public void InsertWorker(WorkerDataModel workerDataModel)
+    {
+        _logger.LogInformation("New data: {json}",
+        JsonSerializer.Serialize(workerDataModel));
+        ArgumentNullException.ThrowIfNull(workerDataModel);
+        workerDataModel.Validate();
+        _workerStorageContract.AddElement(workerDataModel);
+    }
+    public void UpdateWorker(WorkerDataModel workerDataModel)
+    {
+        _logger.LogInformation("Update data: {json}",
+        JsonSerializer.Serialize(workerDataModel));
+        ArgumentNullException.ThrowIfNull(workerDataModel);
+        workerDataModel.Validate();
+        _workerStorageContract.UpdElement(workerDataModel);
+    } 
+public void DeleteWorker(string id)
+    {
+        _logger.LogInformation("Delete by id: {id}", id);
+        if (id.IsEmpty())
+        {
+            throw new ArgumentNullException(nameof(id));
+        }
+        if (!id.IsGuid())
+        {
+            throw new ValidationException("Id is not a unique identifier");
+        }
+        _workerStorageContract.DelElement(id);
+    }
+}
--- a/SmallSoftwareProject/SmallSoftwareBusinessLogic/SmallSoftwareBusinessLogic.csproj
+++ b/SmallSoftwareProject/SmallSoftwareBusinessLogic/SmallSoftwareBusinessLogic.csproj
@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Logging" Version="9.0.2" />
+  </ItemGroup>
+
+    <ItemGroup>
+	    <InternalsVisibleTo Include="SmallSoftwareTests" />
+	    <InternalsVisibleTo Include="DynamicProxyGenAssembly2" />
+    </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\SmallSoftwareContracts\SmallSoftwareContracts.csproj" />
+  </ItemGroup>
+
+</Project>
--- a/SmallSoftwareProject/SmallSoftwareContracts/BusinessLogicsContracts/IManufacturerBusinessLogicContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/BusinessLogicsContracts/IManufacturerBusinessLogicContract.cs
@@ -0,0 +1,17 @@
+using SmallSoftwareContracts.DataModels;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareContracts.BusinessLogicsContracts;
+
+public interface IManufacturerBusinessLogicContract
+{
+    List<ManufacturerDataModel> GetAllManufacturers();
+    ManufacturerDataModel GetManufacturerByData(string data);
+    void InsertManufacturer(ManufacturerDataModel manufacturerDataModel);
+    void UpdateManufacturer(ManufacturerDataModel manufacturerDataModel); 
+    void DeleteManufacturer(string id);
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/BusinessLogicsContracts/IPostBusinessLogicContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/BusinessLogicsContracts/IPostBusinessLogicContract.cs
@@ -0,0 +1,19 @@
+using SmallSoftwareContracts.DataModels;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareContracts.BusinessLogicsContracts;
+
+public interface IPostBusinessLogicContract
+{
+    List<PostDataModel> GetAllPosts(bool onlyActive);
+    List<PostDataModel> GetAllDataOfPost(string postId);
+    PostDataModel GetPostByData(string data);
+    void InsertPost(PostDataModel postDataModel);
+    void UpdatePost(PostDataModel postDataModel);
+    void DeletePost(string id);
+    void RestorePost(string id);
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/BusinessLogicsContracts/IRequestBusinessLogicContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/BusinessLogicsContracts/IRequestBusinessLogicContract.cs
@@ -0,0 +1,22 @@
+using SmallSoftwareContracts.DataModels;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareContracts.BusinessLogicsContracts;
+
+public interface IRequestBusinessLogicContract
+{
+
+    List<RequestDataModel> GetAllRequestsByPeriod(DateTime fromDate, DateTime toDate);
+    List<RequestDataModel> GetAllRequestsByWorkerByPeriod(string workerId, DateTime fromDate, DateTime toDate);
+
+    List<RequestDataModel> GetAllRequestsBySoftwareByPeriod(string softwareId, DateTime fromDate, DateTime toDate);
+
+
+    RequestDataModel GetRequestByData(string data);
+    void InsertRequest(RequestDataModel requestDataModel);
+    void CancelRequest(string id);
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/BusinessLogicsContracts/ISalaryBusinessLogicContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/BusinessLogicsContracts/ISalaryBusinessLogicContract.cs
@@ -0,0 +1,12 @@
+
+using SmallSoftwareContracts.DataModels;
+
+namespace SmallSoftwareContracts.BusinessLogicsContracts;
+
+public interface ISalaryBusinessLogicContract
+{
+    List<SalaryDataModel> GetAllSalariesByPeriod(DateTime fromDate, DateTime toDate); 
+    List<SalaryDataModel> GetAllSalariesByPeriodByWorker(DateTime fromDate, DateTime toDate, string workerId);
+    void CalculateSalaryByMonth(DateTime date);
+
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/BusinessLogicsContracts/ISoftwareBusinessLogicContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/BusinessLogicsContracts/ISoftwareBusinessLogicContract.cs
@@ -0,0 +1,16 @@
+using SmallSoftwareContracts.DataModels;
+
+namespace SmallSoftwareContracts.BusinessLogicsContracts;
+
+public interface ISoftwareBusinessLogicContract
+{
+    List<SoftwareDataModel> GetAllSoftwares(bool onlyActive = true);
+    List<SoftwareDataModel> GetAllSoftwaresByManufacturer(string manufacturerId,
+    bool onlyActive = true);
+    List<SoftwareHistoryDataModel> GetSoftwareHistoryBySoftware(string softwareId);
+    SoftwareDataModel GetSoftwareByData(string data);
+    void InsertSoftware(SoftwareDataModel softwareDataModel);
+    void UpdateSoftware(SoftwareDataModel softwareDataModel);
+    void DeleteSoftware(string id);
+
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/BusinessLogicsContracts/IWorkerBusinessLogicContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/BusinessLogicsContracts/IWorkerBusinessLogicContract.cs
@@ -0,0 +1,17 @@
+using SmallSoftwareContracts.DataModels;
+
+namespace SmallSoftwareContracts.BusinessLogicsContracts;
+
+public interface IWorkerBusinessLogicContract
+{
+    List<WorkerDataModel> GetAllWorkers(bool onlyActive = true);
+    List<WorkerDataModel> GetAllWorkersByPost(string postId, bool onlyActive = true);
+    List<WorkerDataModel> GetAllWorkersByBirthDate(DateTime fromDate, DateTime toDate, bool onlyActive = true);
+    List<WorkerDataModel> GetAllWorkersByEmploymentDate(DateTime fromDate,
+    DateTime toDate, bool onlyActive = true);
+    WorkerDataModel GetWorkerByData(string data);
+    void InsertWorker(WorkerDataModel workerDataModel);
+    void UpdateWorker(WorkerDataModel workerDataModel);
+    void DeleteWorker(string id);
+
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/DataModels/PostDataModel.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/DataModels/PostDataModel.cs
@@ -5,11 +5,10 @@ using SmallSoftwareContracts.Infrastructure;

 namespace SmallSoftwareContracts.DataModels;

-public class PostDataModel(string id, string postId, string postName, PostType 
+public class PostDataModel(string id, string postName, PostType 
    postType, double salary, bool isActual, DateTime changeDate) : IValidation
 {
    public string Id { get; private set; } = id;
-    public string PostId { get; private set; } = postId;
    public string PostName { get; private set; } = postName;
    public PostType PostType { get; private set; } = postType;
    public double Salary { get; private set; } = salary;
@@ -23,12 +22,6 @@ public class PostDataModel(string id, string postId, string postName, PostType
        if (!Id.IsGuid())
            throw new ValidationException("The value in the field Id is not a unique identifier");

-        if (PostId.IsEmpty())
-            throw new ValidationException("Field PostId is empty");
-
-        if (!PostId.IsGuid())
-            throw new ValidationException("The value in the field PostId is not a unique identifier");
-
        if (PostName.IsEmpty())
            throw new ValidationException("Field PostName is empty");

--- a/SmallSoftwareProject/SmallSoftwareContracts/DataModels/RequestDataModel.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/DataModels/RequestDataModel.cs
@@ -7,12 +7,10 @@ using System.Text.RegularExpressions;
 namespace SmallSoftwareContracts.DataModels;


-public class RequestDataModel(string id, string workerId, string email, double sum, 
-    bool isCancel, List<InstallationRequestDataModel> softwares) : IValidation
+public class RequestDataModel(string id, string workerId, string email, double sum,  bool isCancel, List<InstallationRequestDataModel> softwares) : IValidation
 {
    public string Id { get; private set; } = id;
    public string WorkerId { get; private set; } = workerId;
-    public DateTime RequestDate { get; private set; } = DateTime.UtcNow;
    public string Email { get; private set; } = email;
    public double Sum { get; private set; } = sum;
    public bool IsCancel { get; private set; } = isCancel;
--- a/SmallSoftwareProject/SmallSoftwareContracts/Exceptions/ElementExistsException.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/Exceptions/ElementExistsException.cs
@@ -0,0 +1,13 @@
+
+namespace SmallSoftwareContracts.Exceptions;
+public class ElementExistsException : Exception
+{
+    public string ParamName { get; private set; }
+    public string ParamValue { get; private set; }
+    public ElementExistsException(string paramName, string paramValue) :
+    base($"There is already an element with value{paramValue} of parameter { paramName}")
+    {
+        ParamName = paramName;
+        ParamValue = paramValue;
+    }
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/Exceptions/ElementNotFoundException.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/Exceptions/ElementNotFoundException.cs
@@ -0,0 +1,10 @@
+namespace SmallSoftwareContracts.Exceptions;
+
+public class ElementNotFoundException : Exception
+{
+    public string Value { get; private set; }
+    public ElementNotFoundException(string value) : base($"Element not found at value = { value}")
+    {
+        Value = value;
+    }
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/Exceptions/IncorrectDatesException.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/Exceptions/IncorrectDatesException.cs
@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using static System.Runtime.InteropServices.JavaScript.JSType;
+
+namespace SmallSoftwareContracts.Exceptions;
+
+public class IncorrectDatesException : Exception
+{ 
+public IncorrectDatesException(DateTime start, DateTime end) : 
+        base($"The end date must be later than the start date..StartDate: { start: dd.MM.YYYY}.EndDate: {end:dd.MM.YYYY}") { }
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/Exceptions/NullListException.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/Exceptions/NullListException.cs
@@ -0,0 +1,7 @@
+
+namespace SmallSoftwareContracts.Exceptions;
+
+public class NullListException : Exception
+{
+    public NullListException() : base("The returned list is null") { }
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/Exceptions/StorageException.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/Exceptions/StorageException.cs
@@ -0,0 +1,8 @@
+
+
+namespace SmallSoftwareContracts.Exceptions;
+
+public class StorageException : Exception
+{
+    public StorageException(Exception ex) : base($"Error while working in storage: { ex.Message}", ex) { }
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/Extensions/DateTimeExtensions.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/Extensions/DateTimeExtensions.cs
@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareContracts.Extensions;
+
+public static class DateTimeExtensions
+{
+    public static bool IsDateNotOlder(this DateTime date, DateTime olderDate)
+    {
+        return date >= olderDate;
+    }
+}
+
--- a/SmallSoftwareProject/SmallSoftwareContracts/StoragesContracts/IManufacturerStorageContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/StoragesContracts/IManufacturerStorageContract.cs
@@ -0,0 +1,15 @@
+using SmallSoftwareContracts.DataModels;
+
+namespace SmallSoftwareContracts.StoragesContracts;
+
+public interface IManufacturerStorageContract
+{
+    List<ManufacturerDataModel> GetList();
+    ManufacturerDataModel? GetElementById(string id);
+    ManufacturerDataModel? GetElementByName(string name);
+    ManufacturerDataModel? GetElementByOldName(string name);
+    void AddElement(ManufacturerDataModel manufacturerDataModel);
+    void UpdElement(ManufacturerDataModel manufacturerDataModel);
+    void DelElement(string id);
+
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/StoragesContracts/IPostStorageContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/StoragesContracts/IPostStorageContract.cs
@@ -0,0 +1,15 @@
+using SmallSoftwareContracts.DataModels;
+
+namespace SmallSoftwareContracts.StoragesContracts;
+
+public interface IPostStorageContract
+{
+    List<PostDataModel> GetList(bool onlyActual = true);
+    List<PostDataModel> GetPostWithHistory(string postId);
+    PostDataModel? GetElementById(string id);
+    PostDataModel? GetElementByName(string name);
+    void AddElement(PostDataModel postDataModel);
+    void UpdElement(PostDataModel postDataModel);
+    void DelElement(string id);
+    void ResElement(string id);
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/StoragesContracts/IRequestStorageContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/StoragesContracts/IRequestStorageContract.cs
@@ -0,0 +1,17 @@
+using SmallSoftwareContracts.DataModels;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareContracts.StoragesContracts;
+
+public interface IRequestStorageContract
+{
+    List<RequestDataModel> GetList(DateTime? startDate = null, 
+                                DateTime? endDate = null, string? workerId = null, string? softwareId = null);
+    RequestDataModel? GetElementById(string id);
+    void AddElement(RequestDataModel requestDataModel);
+    void DelElement(string id);
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/StoragesContracts/ISalaryStorageContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/StoragesContracts/ISalaryStorageContract.cs
@@ -0,0 +1,15 @@
+using SmallSoftwareContracts.DataModels;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareContracts.StoragesContracts;
+
+public interface ISalaryStorageContract
+{
+    List<SalaryDataModel> GetList(DateTime startDate, DateTime endDate, string? workerId = null);
+    void AddElement(SalaryDataModel salaryDataModel);
+
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/StoragesContracts/ISoftwareStorageContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/StoragesContracts/ISoftwareStorageContract.cs
@@ -0,0 +1,19 @@
+using SmallSoftwareContracts.DataModels;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareContracts.StoragesContracts;
+
+public interface ISoftwareStorageContract
+{
+    List<SoftwareDataModel> GetList(bool onlyActive = true, string? manufacturerId = null);
+    List<SoftwareHistoryDataModel> GetHistoryBySoftwareId(string softwareId);
+    SoftwareDataModel? GetElementById(string id);
+    SoftwareDataModel? GetElementByName(string name);
+    void AddElement(SoftwareDataModel softwareDataModel);
+    void UpdElement(SoftwareDataModel softwareDataModel);
+    void DelElement(string id);
+}
--- a/SmallSoftwareProject/SmallSoftwareContracts/StoragesContracts/IWorkerStorageContract.cs
+++ b/SmallSoftwareProject/SmallSoftwareContracts/StoragesContracts/IWorkerStorageContract.cs
@@ -0,0 +1,20 @@
+using SmallSoftwareContracts.DataModels;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareContracts.StoragesContracts;
+
+public interface IWorkerStorageContract
+{
+    List<WorkerDataModel> GetList(bool onlyActive = true, string? postId =  
+                                  null, DateTime? fromBirthDate = null, DateTime? toBirthDate = null, DateTime?
+                                  fromEmploymentDate = null, DateTime? toEmploymentDate = null);
+    WorkerDataModel? GetElementById(string id);
+    WorkerDataModel? GetElementByFIO(string fio);
+    void AddElement(WorkerDataModel workerDataModel);
+    void UpdElement(WorkerDataModel workerDataModel);
+    void DelElement(string id);
+}
--- a/SmallSoftwareProject/SmallSoftwareProject.sln
+++ b/SmallSoftwareProject/SmallSoftwareProject.sln
@@ -1,12 +1,14 @@

 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio Version 17
-VisualStudioVersion = 17.12.35728.132 d17.12
+VisualStudioVersion = 17.12.35728.132
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SmallSoftwareContracts", "SmallSoftwareContracts\SmallSoftwareContracts.csproj", "{07D2A792-3603-47CB-B5A3-9736E582F496}"
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SmallSoftwareTests", "SmallSoftwareTests\SmallSoftwareTests.csproj", "{A98AC101-F5F5-4270-97D6-B5FA766D3E64}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SmallSoftwareBusinessLogic", "SmallSoftwareBusinessLogic\SmallSoftwareBusinessLogic.csproj", "{C4E0D33E-8DBB-4BB5-8CCE-D2888F754EC7}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -21,6 +23,10 @@ Global
 		{A98AC101-F5F5-4270-97D6-B5FA766D3E64}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{A98AC101-F5F5-4270-97D6-B5FA766D3E64}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{A98AC101-F5F5-4270-97D6-B5FA766D3E64}.Release|Any CPU.Build.0 = Release|Any CPU
+		{C4E0D33E-8DBB-4BB5-8CCE-D2888F754EC7}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{C4E0D33E-8DBB-4BB5-8CCE-D2888F754EC7}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{C4E0D33E-8DBB-4BB5-8CCE-D2888F754EC7}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{C4E0D33E-8DBB-4BB5-8CCE-D2888F754EC7}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
--- a/SmallSoftwareProject/SmallSoftwareTests/BusinessLogicsContractsTests/ManufacturerBusinessLogicContractTests.cs
+++ b/SmallSoftwareProject/SmallSoftwareTests/BusinessLogicsContractsTests/ManufacturerBusinessLogicContractTests.cs
@@ -0,0 +1,446 @@
+using Microsoft.Extensions.Logging;
+using Moq;
+using SmallSoftwareBusinessLogic.Implementations;
+using SmallSoftwareContracts.BusinessLogicsContracts;
+using SmallSoftwareContracts.DataModels;
+using SmallSoftwareContracts.Exceptions;
+using SmallSoftwareContracts.StoragesContracts;
+
+namespace SmallSoftwareTests.BusinessLogicsContractsTests;
+
+[TestFixture]
+internal class ManufacturerBusinessLogicContractTests
+{
+    private IManufacturerBusinessLogicContract _manufacturerBusinessLogicContract;
+    private Mock<IManufacturerStorageContract> _manufacturerStorageContract;
+    [OneTimeSetUp]
+    public void OneTimeSetUp()
+    {
+        _manufacturerStorageContract = new
+        Mock<IManufacturerStorageContract>();
+        _manufacturerBusinessLogicContract = new ManufacturerBusinessLogicContract(_manufacturerStorageContract.Object, new Mock<ILogger>().Object);
+    }
+    [SetUp]
+    public void SetUp()
+    {
+        _manufacturerStorageContract.Reset();
+    }
+    [Test]
+    public void GetAllManufacturers_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var listOriginal = new List<ManufacturerDataModel>()
+    {
+    new(Guid.NewGuid().ToString(), "name 1", null, null),
+    new(Guid.NewGuid().ToString(), "name 2", null, null),
+    new(Guid.NewGuid().ToString(), "name 3", null, null),
+    };
+        _manufacturerStorageContract.Setup(x =>
+        x.GetList()).Returns(listOriginal);
+        //Act
+        var list = _manufacturerBusinessLogicContract.GetAllManufacturers();
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Is.EquivalentTo(listOriginal));
+    }
+    [Test]
+    public void GetAllManufacturers_ReturnEmptyList_Test()
+    {
+        //Arrange
+        _manufacturerStorageContract.Setup(x => x.GetList()).Returns([]);
+        //Act
+        var list = _manufacturerBusinessLogicContract.GetAllManufacturers();
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(0));
+        _manufacturerStorageContract.Verify(x => x.GetList(), Times.Once);
+    }
+    [Test]
+    public void GetAllManufacturers_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.GetAllManufacturers(),
+        Throws.TypeOf<NullListException>());
+        _manufacturerStorageContract.Verify(x => x.GetList(), Times.Once);
+    }
+    [Test]
+    public void GetAllManufacturers_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _manufacturerStorageContract.Setup(x => x.GetList()).Throws(new
+        StorageException(new InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.GetAllManufacturers(),
+        Throws.TypeOf<StorageException>());
+        _manufacturerStorageContract.Verify(x => x.GetList(), Times.Once);
+    }
+    [Test]
+    public void GetManufacturerByData_GetById_ReturnRecord_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        var record = new ManufacturerDataModel(id, "name", null, null);
+        _manufacturerStorageContract.Setup(x =>
+        x.GetElementById(id)).Returns(record);
+        
+    //Act
+        var element =
+        _manufacturerBusinessLogicContract.GetManufacturerByData(id);
+                //Assert
+                Assert.That(element, Is.Not.Null);
+                Assert.That(element.Id, Is.EqualTo(id));
+                _manufacturerStorageContract.Verify(x =>
+                x.GetElementById(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetManufacturerByData_GetByName_ReturnRecord_Test()
+    {
+        //Arrange
+        var manufacturerName = "name";
+        var record = new ManufacturerDataModel(Guid.NewGuid().ToString(),
+        manufacturerName, null, null);
+        _manufacturerStorageContract.Setup(x =>
+        x.GetElementByName(manufacturerName)).Returns(record);
+        //Act
+        var element =
+        _manufacturerBusinessLogicContract.GetManufacturerByData(manufacturerName);
+        //Assert
+        Assert.That(element, Is.Not.Null);
+        Assert.That(element.ManufacturerName, Is.EqualTo(manufacturerName));
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetManufacturerByData_GetByOldName_ReturnRecord_Test()
+    {
+        //Arrange
+        var manufacturerOldName = "name before";
+        var record = new ManufacturerDataModel(Guid.NewGuid().ToString(),
+        "name", manufacturerOldName, null);
+        _manufacturerStorageContract.Setup(x =>
+        x.GetElementByOldName(manufacturerOldName)).Returns(record);
+        //Act
+        var element =
+        _manufacturerBusinessLogicContract.GetManufacturerByData(manufacturerOldName);
+        //Assert
+        Assert.That(element, Is.Not.Null);
+        Assert.That(element.PrevManufacturerName,
+        Is.EqualTo(manufacturerOldName));
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Once);
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementByOldName(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetManufacturerByData_EmptyData_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.GetManufacturerByData(null),
+        Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.GetManufacturerByData(string.Empty),
+        Throws.TypeOf<ArgumentNullException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Never); 
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Never);
+            _manufacturerStorageContract.Verify(x =>
+            x.GetElementByOldName(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void
+    GetManufacturerByData__GetById_NotFoundRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.GetManufacturerByData(Guid.NewGuid().ToString(
+        )), Throws.TypeOf<ElementNotFoundException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Once);
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Never);
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementByOldName(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void
+    GetManufacturerByData_GetByNameOrOldName_NotFoundRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.GetManufacturerByData("name"),
+        Throws.TypeOf<ElementNotFoundException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Never);
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Once);
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementByOldName(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetManufacturerByData_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _manufacturerStorageContract.Setup(x =>
+        x.GetElementById(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        _manufacturerStorageContract.Setup(x =>
+        x.GetElementByName(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.GetManufacturerByData(Guid.NewGuid().ToString(
+        )), Throws.TypeOf<StorageException>());
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.GetManufacturerByData("name"),
+        Throws.TypeOf<StorageException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Once);
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Once);
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementByOldName(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+ 
+    public void
+    GetManufacturerByData_GetByOldName_StorageThrowError_ThrowException_Test()
+        {
+        //Arrange
+        _manufacturerStorageContract.Setup(x =>
+        x.GetElementByOldName(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.GetManufacturerByData("name"),
+        Throws.TypeOf<StorageException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Once);
+        _manufacturerStorageContract.Verify(x =>
+        x.GetElementByOldName(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void InsertManufacturer_CorrectRecord_Test()
+    {
+        //Arrange
+        var flag = false;
+        var record = new ManufacturerDataModel(Guid.NewGuid().ToString(),
+        "name", null, null);
+        _manufacturerStorageContract.Setup(x =>
+        x.AddElement(It.IsAny<ManufacturerDataModel>()))
+        .Callback((ManufacturerDataModel x) =>
+        {
+            flag = x.Id == record.Id && x.ManufacturerName ==
+    record.ManufacturerName;
+        });
+        //Act
+        _manufacturerBusinessLogicContract.InsertManufacturer(record);
+        //Assert
+        _manufacturerStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<ManufacturerDataModel>()), Times.Once);
+        Assert.That(flag);
+    }
+    [Test]
+    public void InsertManufacturer_RecordWithExistsData_ThrowException_Test()
+    {
+        //Arrange
+        _manufacturerStorageContract.Setup(x =>
+        x.AddElement(It.IsAny<ManufacturerDataModel>())).Throws(new
+        ElementExistsException("Data", "Data"));
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.InsertManufacturer(new(Guid.NewGuid().ToString
+        (), "name", null, null)), Throws.TypeOf<ElementExistsException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<ManufacturerDataModel>()), Times.Once);
+    }
+    [Test]
+    public void InsertManufacturer_NullRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.InsertManufacturer(null),
+        Throws.TypeOf<ArgumentNullException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<ManufacturerDataModel>()), Times.Never);
+    } 
+    [Test]
+    public void InsertManufacturer_InvalidRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.InsertManufacturer(new
+        ManufacturerDataModel("id", "name", null, null)),
+        Throws.TypeOf<ValidationException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<ManufacturerDataModel>()), Times.Never);
+    }
+    [Test]
+    public void InsertManufacturer_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _manufacturerStorageContract.Setup(x =>
+        x.AddElement(It.IsAny<ManufacturerDataModel>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.InsertManufacturer(new(Guid.NewGuid().ToString
+        (), "name", null, null)), Throws.TypeOf<StorageException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<ManufacturerDataModel>()), Times.Once);
+    }
+    [Test]
+    public void UpdateManufacturer_CorrectRecord_Test()
+    {
+        //Arrange
+        var flag = false;
+        var record = new ManufacturerDataModel(Guid.NewGuid().ToString(),
+        "name", null, null);
+        _manufacturerStorageContract.Setup(x =>
+        x.UpdElement(It.IsAny<ManufacturerDataModel>()))
+        .Callback((ManufacturerDataModel x) =>
+        {
+            flag = x.Id == record.Id && x.ManufacturerName ==
+    record.ManufacturerName;
+        });
+        //Act
+        _manufacturerBusinessLogicContract.UpdateManufacturer(record);
+        //Assert
+        _manufacturerStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<ManufacturerDataModel>()), Times.Once);
+        Assert.That(flag);
+    }
+    [Test]
+    public void
+    UpdateManufacturer_RecordWithIncorrectData_ThrowException_Test()
+    {
+        //Arrange
+        _manufacturerStorageContract.Setup(x =>
+        x.UpdElement(It.IsAny<ManufacturerDataModel>())).Throws(new
+        ElementNotFoundException(""));
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.UpdateManufacturer(new(Guid.NewGuid().ToString
+        (), "name", null, null)), Throws.TypeOf<ElementNotFoundException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<ManufacturerDataModel>()), Times.Once); 
+    }
+    [Test]
+    public void UpdateManufacturer_RecordWithExistsData_ThrowException_Test()
+    {
+        //Arrange
+        _manufacturerStorageContract.Setup(x =>
+        x.UpdElement(It.IsAny<ManufacturerDataModel>())).Throws(new
+        ElementExistsException("Data", "Data"));
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.UpdateManufacturer(new(Guid.NewGuid().ToString
+        (), "name", null, null)), Throws.TypeOf<ElementExistsException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<ManufacturerDataModel>()), Times.Once);
+    }
+    [Test]
+    public void UpdateManufacturer_NullRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.UpdateManufacturer(null),
+        Throws.TypeOf<ArgumentNullException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<ManufacturerDataModel>()), Times.Never);
+    }
+    [Test]
+    public void UpdateManufacturer_InvalidRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.UpdateManufacturer(new
+        ManufacturerDataModel("id", "name", null, null)),
+        Throws.TypeOf<ValidationException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<ManufacturerDataModel>()), Times.Never);
+    }
+    [Test]
+    public void UpdateManufacturer_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _manufacturerStorageContract.Setup(x =>
+        x.UpdElement(It.IsAny<ManufacturerDataModel>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.UpdateManufacturer(new(Guid.NewGuid().ToString
+        (), "name", null, null)), Throws.TypeOf<StorageException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<ManufacturerDataModel>()), Times.Once);
+    }
+    [Test]
+    public void DeleteManufacturer_CorrectRecord_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        var flag = false;
+        _manufacturerStorageContract.Setup(x => x.DelElement(It.Is((string x)
+        => x == id))).Callback(() => { flag = true; });
+        //Act 
+        _manufacturerBusinessLogicContract.DeleteManufacturer(id);
+        //Assert
+        _manufacturerStorageContract.Verify(x =>
+        x.DelElement(It.IsAny<string>()), Times.Once);
+        Assert.That(flag);
+    }
+    [Test]
+    public void DeleteManufacturer_RecordWithIncorrectId_ThrowException_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        _manufacturerStorageContract.Setup(x =>
+        x.DelElement(It.IsAny<string>())).Throws(new ElementNotFoundException(id));
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.DeleteManufacturer(Guid.NewGuid().ToString()),
+        Throws.TypeOf<ElementNotFoundException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.DelElement(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void DeleteManufacturer_IdIsNullOrEmpty_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.DeleteManufacturer(null),
+        Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.DeleteManufacturer(string.Empty),
+        Throws.TypeOf<ArgumentNullException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.DelElement(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void DeleteManufacturer_IdIsNotGuid_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.DeleteManufacturer("id"),
+        Throws.TypeOf<ValidationException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.DelElement(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void DeleteManufacturer_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _manufacturerStorageContract.Setup(x =>
+        x.DelElement(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _manufacturerBusinessLogicContract.DeleteManufacturer(Guid.NewGuid().ToString()),
+        Throws.TypeOf<StorageException>());
+        _manufacturerStorageContract.Verify(x =>
+        x.DelElement(It.IsAny<string>()), Times.Once);
+    }
+}
--- a/SmallSoftwareProject/SmallSoftwareTests/BusinessLogicsContractsTests/PostBusinessLogicContractTests.cs
+++ b/SmallSoftwareProject/SmallSoftwareTests/BusinessLogicsContractsTests/PostBusinessLogicContractTests.cs
@@ -0,0 +1,567 @@
+using Microsoft.Extensions.Logging;
+using Moq;
+using SmallSoftwareBusinessLogic.Implementations;
+using SmallSoftwareContracts.DataModels;
+using SmallSoftwareContracts.Enums;
+using SmallSoftwareContracts.Exceptions;
+using SmallSoftwareContracts.StoragesContracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareTests.BusinessLogicsContractsTests;
+
+[TestFixture]
+internal class PostBusinessLogicContractTests
+{
+    private PostBusinessLogicContract _postBusinessLogicContract;
+    private Mock<IPostStorageContract> _postStorageContract;
+    [OneTimeSetUp]
+    public void OneTimeSetUp()
+    {
+        _postStorageContract = new Mock<IPostStorageContract>();
+        _postBusinessLogicContract = new
+        PostBusinessLogicContract(_postStorageContract.Object, new
+        Mock<ILogger>().Object);
+    }
+    [SetUp]
+    public void SetUp()
+    {
+        _postStorageContract.Reset();
+    }
+    [Test]
+    public void GetAllPosts_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var listOriginal = new List<PostDataModel>()
+        {
+        new(Guid.NewGuid().ToString(),"name 1", PostType.SoftInstaller,
+        10, true, DateTime.UtcNow),
+        new(Guid.NewGuid().ToString(), "name 2", PostType.SoftInstaller,
+        10, false, DateTime.UtcNow),
+        new(Guid.NewGuid().ToString(), "name 3", PostType.SoftInstaller,
+        10, true, DateTime.UtcNow),
+        };
+        _postStorageContract.Setup(x =>
+        x.GetList(It.IsAny<bool>())).Returns(listOriginal);
+        //Act
+        var listOnlyActive = _postBusinessLogicContract.GetAllPosts(true);
+        var listAll = _postBusinessLogicContract.GetAllPosts(false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null);
+            Assert.That(listAll, Is.Not.Null);
+            Assert.That(listOnlyActive, Is.EquivalentTo(listOriginal));
+            Assert.That(listAll, Is.EquivalentTo(listOriginal));
+        });
+        _postStorageContract.Verify(x => x.GetList(true), Times.Once);
+        _postStorageContract.Verify(x => x.GetList(false), Times.Once);
+    }
+    [Test]
+    public void GetAllPosts_ReturnEmptyList_Test()
+    { 
+        //Arrange
+        _postStorageContract.Setup(x =>
+        x.GetList(It.IsAny<bool>())).Returns([]);
+        //Act
+        var listOnlyActive = _postBusinessLogicContract.GetAllPosts(true);
+        var listAll = _postBusinessLogicContract.GetAllPosts(false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null);
+            Assert.That(listAll, Is.Not.Null);
+            Assert.That(listOnlyActive, Has.Count.EqualTo(0));
+            Assert.That(listAll, Has.Count.EqualTo(0));
+        });
+        _postStorageContract.Verify(x => x.GetList(It.IsAny<bool>()),
+        Times.Exactly(2));
+    }
+    [Test]
+    public void GetAllPosts_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _postBusinessLogicContract.GetAllPosts(It.IsAny<bool>()),
+        Throws.TypeOf<NullListException>());
+        _postStorageContract.Verify(x => x.GetList(It.IsAny<bool>()),
+        Times.Once);
+    }
+    [Test]
+    public void GetAllPosts_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _postStorageContract.Setup(x =>
+        x.GetList(It.IsAny<bool>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _postBusinessLogicContract.GetAllPosts(It.IsAny<bool>()),
+        Throws.TypeOf<StorageException>());
+        _postStorageContract.Verify(x => x.GetList(It.IsAny<bool>()),
+        Times.Once);
+    }
+    [Test]
+    public void GetAllDataOfPost_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var postId = Guid.NewGuid().ToString();
+        var listOriginal = new List<PostDataModel>()
+        {
+        new(postId, "name 1", PostType.SoftInstaller, 10, true,
+        DateTime.UtcNow),
+        new(postId, "name 2", PostType.SoftInstaller, 10, false,
+        DateTime.UtcNow)
+        };
+        _postStorageContract.Setup(x =>
+        x.GetPostWithHistory(It.IsAny<string>())).Returns(listOriginal);
+        //Act
+        var list = _postBusinessLogicContract.GetAllDataOfPost(postId);
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(2)); 
+        _postStorageContract.Verify(x => x.GetPostWithHistory(postId),
+        Times.Once);
+        }
+    [Test]
+    public void GetAllDataOfPost_ReturnEmptyList_Test()
+    {
+        //Arrange
+        _postStorageContract.Setup(x =>
+        x.GetPostWithHistory(It.IsAny<string>())).Returns([]);
+        //Act
+        var list =
+        _postBusinessLogicContract.GetAllDataOfPost(Guid.NewGuid().ToString());
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(0));
+        _postStorageContract.Verify(x =>
+        x.GetPostWithHistory(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetAllDataOfPost_PostIdIsNullOrEmpty_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _postBusinessLogicContract.GetAllDataOfPost(null),
+        Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _postBusinessLogicContract.GetAllDataOfPost(string.Empty),
+        Throws.TypeOf<ArgumentNullException>());
+        _postStorageContract.Verify(x =>
+        x.GetPostWithHistory(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetAllDataOfPost_PostIdIsNotGuid_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _postBusinessLogicContract.GetAllDataOfPost("id"),
+        Throws.TypeOf<ValidationException>());
+        _postStorageContract.Verify(x =>
+        x.GetPostWithHistory(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetAllDataOfPost_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _postBusinessLogicContract.GetAllDataOfPost(Guid.NewGuid().ToString()),
+        Throws.TypeOf<NullListException>());
+        _postStorageContract.Verify(x =>
+        x.GetPostWithHistory(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetAllDataOfPost_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _postStorageContract.Setup(x =>
+        x.GetPostWithHistory(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert 
+        Assert.That(() =>
+        _postBusinessLogicContract.GetAllDataOfPost(Guid.NewGuid().ToString()),
+        Throws.TypeOf<StorageException>());
+        _postStorageContract.Verify(x =>
+        x.GetPostWithHistory(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetPostByData_GetById_ReturnRecord_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        var record = new PostDataModel(id, "name", PostType.SoftInstaller, 10,
+        true, DateTime.UtcNow);
+        _postStorageContract.Setup(x =>
+        x.GetElementById(id)).Returns(record);
+        //Act
+        var element = _postBusinessLogicContract.GetPostByData(id);
+        //Assert
+        Assert.That(element, Is.Not.Null);
+        Assert.That(element.Id, Is.EqualTo(id));
+        _postStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetPostByData_GetByName_ReturnRecord_Test()
+    {
+        //Arrange
+        var postName = "name";
+        var record = new PostDataModel(Guid.NewGuid().ToString(), postName,
+        PostType.SoftInstaller, 10, true, DateTime.UtcNow);
+        _postStorageContract.Setup(x =>
+        x.GetElementByName(postName)).Returns(record);
+        //Act
+        var element = _postBusinessLogicContract.GetPostByData(postName);
+        //Assert
+        Assert.That(element, Is.Not.Null);
+        Assert.That(element.PostName, Is.EqualTo(postName));
+        _postStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetPostByData_EmptyData_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _postBusinessLogicContract.GetPostByData(null),
+        Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _postBusinessLogicContract.GetPostByData(string.Empty),
+        Throws.TypeOf<ArgumentNullException>());
+        _postStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Never);
+        _postStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetPostByData_GetById_NotFoundRecord_ThrowException_Test()
+    {
+        //Act&Assert
+    Assert.That(() =>
+    _postBusinessLogicContract.GetPostByData(Guid.NewGuid().ToString()),
+    Throws.TypeOf<ElementNotFoundException>());
+        _postStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Once);
+        _postStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetPostByData_GetByName_NotFoundRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _postBusinessLogicContract.GetPostByData("name"),
+        Throws.TypeOf<ElementNotFoundException>());
+        _postStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Never);
+        _postStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetPostByData_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _postStorageContract.Setup(x =>
+        x.GetElementById(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        _postStorageContract.Setup(x =>
+        x.GetElementByName(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _postBusinessLogicContract.GetPostByData(Guid.NewGuid().ToString()),
+        Throws.TypeOf<StorageException>());
+        Assert.That(() => _postBusinessLogicContract.GetPostByData("name"),
+        Throws.TypeOf<StorageException>());
+        _postStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Once);
+        _postStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void InsertPost_CorrectRecord_Test()
+    {
+        //Arrange
+        var flag = false;
+        var record = new PostDataModel(Guid.NewGuid().ToString(), "name",
+        PostType.Supervisor, 10, true, DateTime.UtcNow.AddDays(-1));
+        _postStorageContract.Setup(x =>
+        x.AddElement(It.IsAny<PostDataModel>()))
+        .Callback((PostDataModel x) =>
+        {
+            flag = x.Id == record.Id && x.PostName ==
+    record.PostName && x.PostType == record.PostType && x.Salary == record.Salary &&
+    x.ChangeDate == record.ChangeDate;
+        });
+        //Act
+        _postBusinessLogicContract.InsertPost(record);
+        //Assert
+        _postStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<PostDataModel>()), Times.Once);
+        Assert.That(flag);
+    }
+    [Test]
+    public void InsertPost_RecordWithExistsData_ThrowException_Test()
+    {
+        //Arrange
+        _postStorageContract.Setup(x =>
+        x.AddElement(It.IsAny<PostDataModel>())).Throws(new
+        ElementExistsException("Data", "Data"));
+        //Act&Assert
+        Assert.That(() =>
+        _postBusinessLogicContract.InsertPost(new(Guid.NewGuid().ToString(), "name",
+        PostType.Supervisor, 10, true, DateTime.UtcNow)),
+        Throws.TypeOf<ElementExistsException>());
+        _postStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<PostDataModel>()), Times.Once);
+    }
+    [Test]
+    public void InsertPost_NullRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _postBusinessLogicContract.InsertPost(null),
+        Throws.TypeOf<ArgumentNullException>());
+        _postStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<PostDataModel>()), Times.Never);
+    }
+    [Test]
+    public void InsertPost_InvalidRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _postBusinessLogicContract.InsertPost(new
+        PostDataModel("id", "name", PostType.Supervisor, 10, true, DateTime.UtcNow)),
+        Throws.TypeOf<ValidationException>());
+        _postStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<PostDataModel>()), Times.Never);
+    }
+    [Test]
+    public void InsertPost_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _postStorageContract.Setup(x =>
+        x.AddElement(It.IsAny<PostDataModel>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _postBusinessLogicContract.InsertPost(new(Guid.NewGuid().ToString(), "name",
+        PostType.Supervisor, 10, true, DateTime.UtcNow)),
+        Throws.TypeOf<StorageException>());
+        _postStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<PostDataModel>()), Times.Once);
+    }
+    [Test]
+    public void UpdatePost_CorrectRecord_Test()
+    {
+        //Arrange
+        var flag = false;
+        var record = new PostDataModel(Guid.NewGuid().ToString(), "name",
+        PostType.Supervisor, 10, true, DateTime.UtcNow.AddDays(-1));
+        _postStorageContract.Setup(x =>
+        x.UpdElement(It.IsAny<PostDataModel>()))
+    .Callback((PostDataModel x) =>
+    {
+        flag = x.Id == record.Id && x.PostName ==
+    record.PostName && x.PostType == record.PostType && x.Salary == record.Salary &&
+    x.ChangeDate == record.ChangeDate;
+    });
+        //Act
+        _postBusinessLogicContract.UpdatePost(record);
+        //Assert
+        _postStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<PostDataModel>()), Times.Once);
+        Assert.That(flag);
+    }
+    [Test]
+    public void UpdatePost_RecordWithIncorrectData_ThrowException_Test()
+    {
+        //Arrange
+        _postStorageContract.Setup(x =>
+        x.UpdElement(It.IsAny<PostDataModel>())).Throws(new
+        ElementNotFoundException(""));
+        //Act&Assert
+        Assert.That(() =>
+        _postBusinessLogicContract.UpdatePost(new(Guid.NewGuid().ToString(), "name",
+        PostType.Supervisor, 10, true, DateTime.UtcNow)),
+        Throws.TypeOf<ElementNotFoundException>());
+        _postStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<PostDataModel>()), Times.Once);
+    }
+    [Test]
+    public void UpdatePost_RecordWithExistsData_ThrowException_Test()
+    {
+        //Arrange
+        _postStorageContract.Setup(x =>
+        x.UpdElement(It.IsAny<PostDataModel>())).Throws(new
+        ElementExistsException("Data", "Data"));
+        //Act&Assert
+        Assert.That(() =>
+        _postBusinessLogicContract.UpdatePost(new(Guid.NewGuid().ToString(), "anme",
+        PostType.Supervisor, 10, true, DateTime.UtcNow)),
+        Throws.TypeOf<ElementExistsException>());
+        _postStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<PostDataModel>()), Times.Once);
+    }
+    [Test]
+    public void UpdatePost_NullRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _postBusinessLogicContract.UpdatePost(null),
+        Throws.TypeOf<ArgumentNullException>());
+        _postStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<PostDataModel>()), Times.Never);
+    }
+    [Test]
+    public void UpdatePost_InvalidRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _postBusinessLogicContract.UpdatePost(new
+        PostDataModel("id", "name", PostType.Supervisor, 10, true, DateTime.UtcNow)),
+        Throws.TypeOf<ValidationException>());
+    _postStorageContract.Verify(x =>
+    x.UpdElement(It.IsAny<PostDataModel>()), Times.Never);
+    }
+    [Test]
+    public void UpdatePost_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _postStorageContract.Setup(x =>
+        x.UpdElement(It.IsAny<PostDataModel>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _postBusinessLogicContract.UpdatePost(new(Guid.NewGuid().ToString(), "name",
+        PostType.Supervisor, 10, true, DateTime.UtcNow)),
+        Throws.TypeOf<StorageException>());
+        _postStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<PostDataModel>()), Times.Once);
+    }
+    [Test]
+    public void DeletePost_CorrectRecord_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        var flag = false;
+        _postStorageContract.Setup(x => x.DelElement(It.Is((string x) => x ==
+        id))).Callback(() => { flag = true; });
+        //Act
+        _postBusinessLogicContract.DeletePost(id);
+        //Assert
+        _postStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Once);
+        Assert.That(flag);
+    }
+    [Test]
+    public void DeletePost_RecordWithIncorrectId_ThrowException_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        _postStorageContract.Setup(x =>
+        x.DelElement(It.IsAny<string>())).Throws(new ElementNotFoundException(id));
+        //Act&Assert
+        Assert.That(() =>
+        _postBusinessLogicContract.DeletePost(Guid.NewGuid().ToString()),
+        Throws.TypeOf<ElementNotFoundException>());
+        _postStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Once);
+    }
+    [Test]
+    public void DeletePost_IdIsNullOrEmpty_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _postBusinessLogicContract.DeletePost(null),
+        Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _postBusinessLogicContract.DeletePost(string.Empty),
+        Throws.TypeOf<ArgumentNullException>());
+        _postStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Never);
+    }
+[Test]
+    public void DeletePost_IdIsNotGuid_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _postBusinessLogicContract.DeletePost("id"),
+        Throws.TypeOf<ValidationException>());
+        _postStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Never);
+    }
+    [Test]
+    public void DeletePost_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _postStorageContract.Setup(x =>
+        x.DelElement(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _postBusinessLogicContract.DeletePost(Guid.NewGuid().ToString()),
+        Throws.TypeOf<StorageException>());
+        _postStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Once);
+    }
+    [Test]
+    public void RestorePost_CorrectRecord_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        var flag = false;
+        _postStorageContract.Setup(x => x.ResElement(It.Is((string x) => x ==
+        id))).Callback(() => { flag = true; });
+        //Act
+        _postBusinessLogicContract.RestorePost(id);
+        //Assert
+        _postStorageContract.Verify(x => x.ResElement(It.IsAny<string>()),
+        Times.Once);
+        Assert.That(flag);
+    }
+    [Test]
+    public void RestorePost_RecordWithIncorrectId_ThrowException_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        _postStorageContract.Setup(x =>
+        x.ResElement(It.IsAny<string>())).Throws(new ElementNotFoundException(id));
+        //Act&Assert
+        Assert.That(() =>
+        _postBusinessLogicContract.RestorePost(Guid.NewGuid().ToString()),
+        Throws.TypeOf<ElementNotFoundException>());
+        _postStorageContract.Verify(x => x.ResElement(It.IsAny<string>()),
+        Times.Once);
+    }
+    [Test]
+    public void RestorePost_IdIsNullOrEmpty_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _postBusinessLogicContract.RestorePost(null),
+        Throws.TypeOf<ArgumentNullException>());
+    Assert.That(() =>
+    _postBusinessLogicContract.RestorePost(string.Empty),
+    Throws.TypeOf<ArgumentNullException>());
+        _postStorageContract.Verify(x => x.ResElement(It.IsAny<string>()),
+        Times.Never);
+    }
+    [Test]
+    public void RestorePost_IdIsNotGuid_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _postBusinessLogicContract.RestorePost("id"),
+        Throws.TypeOf<ValidationException>());
+        _postStorageContract.Verify(x => x.ResElement(It.IsAny<string>()),
+        Times.Never);
+    }
+    [Test]
+    public void RestorePost_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _postStorageContract.Setup(x =>
+        x.ResElement(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _postBusinessLogicContract.RestorePost(Guid.NewGuid().ToString()),
+        Throws.TypeOf<StorageException>());
+        _postStorageContract.Verify(x => x.ResElement(It.IsAny<string>()),
+        Times.Once);
+    }
+}
+
--- a/SmallSoftwareProject/SmallSoftwareTests/BusinessLogicsContractsTests/RequestBusinessLogicContractTests.cs
+++ b/SmallSoftwareProject/SmallSoftwareTests/BusinessLogicsContractsTests/RequestBusinessLogicContractTests.cs
@@ -0,0 +1,535 @@
+using Microsoft.Extensions.Logging;
+using Moq;
+using SmallSoftwareBusinessLogic.Implementations;
+using SmallSoftwareContracts.DataModels;
+using SmallSoftwareContracts.Exceptions;
+using SmallSoftwareContracts.StoragesContracts;
+
+
+namespace SmallSoftwareTests.BusinessLogicsContractsTests;
+
+[TestFixture]
+internal class RequestBusinessLogicContractTests
+{
+    private RequestBusinessLogicContract _requestBusinessLogicContract;
+    private Mock<IRequestStorageContract> _requestStorageContract;
+    [OneTimeSetUp]
+    public void OneTimeSetUp()
+
+    {
+    _requestStorageContract = new Mock<IRequestStorageContract>();
+    _requestBusinessLogicContract = new
+    RequestBusinessLogicContract(_requestStorageContract.Object, new
+    Mock<ILogger>().Object);
+    }
+    [SetUp]
+    public void SetUp()
+    {
+        _requestStorageContract.Reset();
+    }
+    [Test]
+    public void GetAllRequestsByPeriod_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var date = DateTime.UtcNow;
+        var listOriginal = new List<RequestDataModel>()
+        {
+            new(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 10, false, [new InstallationRequestDataModel(Guid.NewGuid().ToString(),Guid.NewGuid().ToString(), 5)]),
+            new(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 10, false, []), new(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 10, false, []),
+        };
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), It.IsAny<string>())).Returns(listOriginal);
+        //Act
+        var list = _requestBusinessLogicContract.GetAllRequestsByPeriod(date,
+        date.AddDays(1));
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Is.EquivalentTo(listOriginal));
+        _requestStorageContract.Verify(x => x.GetList(date, date.AddDays(1), null, null), Times.Once);
+    }
+    [Test]
+    public void GetAllRequestsByPeriod_ReturnEmptyList_Test()
+    {
+        //Arrange
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(),
+        It.IsAny<string>())).Returns([]);
+        //Act
+        var list =
+        _requestBusinessLogicContract.GetAllRequestsByPeriod(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1));
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(0));
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetAllRequestsByPeriod_IncorrectDates_ThrowException_Test()
+    { 
+    //Arrange
+    var date = DateTime.UtcNow;
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsByPeriod(date, date),
+        Throws.TypeOf<IncorrectDatesException>());
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsByPeriod(date, date.AddSeconds(-1)),
+        Throws.TypeOf<IncorrectDatesException>());
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetAllRequestsByPeriod_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsByPeriod(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1)), Throws.TypeOf<NullListException>());
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(),
+        It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetAllRequestsByPeriod_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsByPeriod(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1)), Throws.TypeOf<StorageException>());
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetAllRequestsByWorkerByPeriod_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var date = DateTime.UtcNow;
+        var workerId = Guid.NewGuid().ToString();
+        var listOriginal = new List<RequestDataModel>()
+        {
+            new(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 10, false, [new InstallationRequestDataModel(Guid.NewGuid().ToString(),Guid.NewGuid().ToString(), 5)]),
+            new(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 10, false, []), new(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 10, false, []),
+        };
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>())).Returns(listOriginal);
+        //Act 
+        var list =
+       _requestBusinessLogicContract.GetAllRequestsByWorkerByPeriod(workerId, date,
+        date.AddDays(1));
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Is.EquivalentTo(listOriginal));
+        _requestStorageContract.Verify(x => x.GetList(date, date.AddDays(1),
+        workerId, null), Times.Once);
+    }
+    [Test]
+    public void GetAllRequestsByWorkerByPeriod_ReturnEmptyList_Test()
+    {
+        //Arrange
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>())).Returns([]);
+        //Act
+        var list =
+        _requestBusinessLogicContract.GetAllRequestsByWorkerByPeriod(Guid.NewGuid().ToString(),
+        DateTime.UtcNow, DateTime.UtcNow.AddDays(1));
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(0));
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void
+    GetAllRequestsByWorkerByPeriod_IncorrectDates_ThrowException_Test()
+    {
+        //Arrange
+        var date = DateTime.UtcNow;
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsByWorkerByPeriod(Guid.NewGuid().ToString(),
+        date, date), Throws.TypeOf<IncorrectDatesException>());
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsByWorkerByPeriod(Guid.NewGuid().ToString(),
+        date, date.AddSeconds(-1)), Throws.TypeOf<IncorrectDatesException>());
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void
+    GetAllRequestsByWorkerByPeriod_WorkerIdIsNullOrEmpty_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsByWorkerByPeriod(null, DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1)), Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsByWorkerByPeriod(string.Empty,
+        DateTime.UtcNow, DateTime.UtcNow.AddDays(1)),
+        Throws.TypeOf<ArgumentNullException>());
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetAllRequestsByWorkerByPeriod_WorkerIdIsNotGuid_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsByWorkerByPeriod("workerId",
+        DateTime.UtcNow, DateTime.UtcNow.AddDays(1)),
+        Throws.TypeOf<ValidationException>());
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetAllRequestsByWorkerByPeriod_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsByWorkerByPeriod(Guid.NewGuid().ToString(),
+        DateTime.UtcNow, DateTime.UtcNow.AddDays(1)),
+        Throws.TypeOf<NullListException>());
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void
+    GetAllRequestsByWorkerByPeriod_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsByWorkerByPeriod(Guid.NewGuid().ToString(),
+        DateTime.UtcNow, DateTime.UtcNow.AddDays(1)), Throws.TypeOf<StorageException>());
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>()), Times.Once);
+    }
+    
+    [Test]
+    public void GetAllRequestsBySoftwareByPeriod_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var date = DateTime.UtcNow;
+        var softwareId = Guid.NewGuid().ToString();
+        var listOriginal = new List<RequestDataModel>()
+        {
+        new(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 10, false, [new InstallationRequestDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 5)]),
+        new(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 10, false, []),
+        new(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 10, false, []),
+        };
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>())).Returns(listOriginal);
+        //Act
+        var list =
+        _requestBusinessLogicContract.GetAllRequestsBySoftwareByPeriod(softwareId, date,
+        date.AddDays(1));
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Is.EquivalentTo(listOriginal));
+        _requestStorageContract.Verify(x => x.GetList(date, date.AddDays(1), null, softwareId), Times.Once);
+    }
+    [Test]
+    public void GetAllRequestsBySoftwareByPeriod_ReturnEmptyList_Test()
+    {
+        //Arrange
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>())).Returns([]);
+        //Act
+        var list =
+        _requestBusinessLogicContract.GetAllRequestsBySoftwareByPeriod(Guid.NewGuid().ToString()
+        , DateTime.UtcNow, DateTime.UtcNow.AddDays(1));
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(0));
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void
+    GetAllRequestsBySoftwareByPeriod_IncorrectDates_ThrowException_Test()
+    {
+        //Arrange
+        var date = DateTime.UtcNow;
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsBySoftwareByPeriod(Guid.NewGuid().ToString()
+        , date, date), Throws.TypeOf<IncorrectDatesException>());
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsBySoftwareByPeriod(Guid.NewGuid().ToString()
+        , date, date.AddSeconds(-1)), Throws.TypeOf<IncorrectDatesException>());
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void
+    GetAllRequestsBySoftwareByPeriod_SoftwareIdIsNullOrEmpty_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsBySoftwareByPeriod(null, DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1)), Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsBySoftwareByPeriod(string.Empty, DateTime.UtcNow, DateTime.UtcNow.AddDays(1)),
+        Throws.TypeOf<ArgumentNullException>());
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void
+    GetAllRequestsBySoftwareByPeriod_SoftwareIdIsNotGuid_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsBySoftwareByPeriod("softwareId",
+        DateTime.UtcNow, DateTime.UtcNow.AddDays(1)),
+        Throws.TypeOf<ValidationException>());
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetAllRequestsBySoftwareByPeriod_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsBySoftwareByPeriod(Guid.NewGuid().ToString()
+        , DateTime.UtcNow, DateTime.UtcNow.AddDays(1)),
+        Throws.TypeOf<NullListException>());
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void
+    GetAllRequestsBySoftwareByPeriod_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetAllRequestsBySoftwareByPeriod(Guid.NewGuid().ToString()
+        , DateTime.UtcNow, DateTime.UtcNow.AddDays(1)),
+        Throws.TypeOf<StorageException>());
+        _requestStorageContract.Verify(x => x.GetList(It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<string>(), 
+        It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetRequestByData_GetById_ReturnRecord_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        var record = new RequestDataModel(id, Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 10, false, [new InstallationRequestDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 5)]);
+        _requestStorageContract.Setup(x =>
+        x.GetElementById(id)).Returns(record); 
+    //Act
+    var element = _requestBusinessLogicContract.GetRequestByData(id);
+        //Assert
+        Assert.That(element, Is.Not.Null);
+        Assert.That(element.Id, Is.EqualTo(id));
+        _requestStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetRequestByData_EmptyData_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _requestBusinessLogicContract.GetRequestByData(null),
+        Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetRequestByData(string.Empty),
+        Throws.TypeOf<ArgumentNullException>());
+        _requestStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetRequestByData_IdIsNotGuid_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _requestBusinessLogicContract.GetRequestByData("requestId"),
+        Throws.TypeOf<ValidationException>());
+        _requestStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetRequestByData_GetById_NotFoundRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetRequestByData(Guid.NewGuid().ToString()),
+        Throws.TypeOf<ElementNotFoundException>());
+        _requestStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetRequestByData_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _requestStorageContract.Setup(x =>
+        x.GetElementById(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.GetRequestByData(Guid.NewGuid().ToString()),
+        Throws.TypeOf<StorageException>());
+        _requestStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void InsertRequest_CorrectRecord_Test()
+    {
+        //Arrange
+        var flag = false; 
+        var record = new RequestDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), "valid.email@example.com", 10, false, 
+            [new InstallationRequestDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 5)]);
+        _requestStorageContract.Setup(x => x.AddElement(It.IsAny<RequestDataModel>()))
+        .Callback((RequestDataModel x) =>
+        {
+            flag = x.Id == record.Id && x.WorkerId == record.WorkerId && x.IsCancel ==
+            record.IsCancel && x.Softwares.Count == record.Softwares.Count &&
+            x.Softwares.First().SoftwareId ==
+            record.Softwares.First().SoftwareId &&
+            x.Softwares.First().RequestId ==
+            record.Softwares.First().RequestId &&
+            x.Softwares.First().Count ==
+            record.Softwares.First().Count;
+        });
+        //Act
+        _requestBusinessLogicContract.InsertRequest(record);
+        //Assert
+        _requestStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<RequestDataModel>()), Times.Once);
+        Assert.That(flag);
+    }
+    [Test]
+    public void InsertRequest_RecordWithExistsData_ThrowException_Test()
+    {
+        //Arrange
+        _requestStorageContract.Setup(x =>
+        x.AddElement(It.IsAny<RequestDataModel>())).Throws(new
+        ElementExistsException("Data", "Data"));
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.InsertRequest(new(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), "test@example.com", 10,false, 
+        [new InstallationRequestDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 5)])), Throws.TypeOf<ElementExistsException>());
+        _requestStorageContract.Verify(x => x.AddElement(It.IsAny<RequestDataModel>()), Times.Once);
+    }
+    [Test]
+    public void InsertRequest_NullRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _requestBusinessLogicContract.InsertRequest(null),
+        Throws.TypeOf<ArgumentNullException>());
+        _requestStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<RequestDataModel>()), Times.Never);
+    }
+    [Test]
+    public void InsertRequest_InvalidRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _requestBusinessLogicContract.InsertRequest(new RequestDataModel("id", Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 10, false, [])), Throws.TypeOf<ValidationException>());
+    _requestStorageContract.Verify(x =>
+    x.AddElement(It.IsAny<RequestDataModel>()), Times.Never);
+    }
+    [Test]
+    public void InsertRequest_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _requestStorageContract.Setup(x =>
+        x.AddElement(It.IsAny<RequestDataModel>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.InsertRequest(new(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), "test@example.com", 10, false, [new InstallationRequestDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 5)])), Throws.TypeOf<StorageException>());
+        _requestStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<RequestDataModel>()), Times.Once);
+    }
+    [Test]
+    public void CancelRequest_CorrectRecord_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        var flag = false;
+        _requestStorageContract.Setup(x => x.DelElement(It.Is((string x) => x ==
+        id))).Callback(() => { flag = true; });
+        //Act
+        _requestBusinessLogicContract.CancelRequest(id);
+        //Assert
+        _requestStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Once);
+        Assert.That(flag);
+    }
+    [Test]
+    public void CancelRequest_RecordWithIncorrectId_ThrowException_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        _requestStorageContract.Setup(x =>
+        x.DelElement(It.IsAny<string>())).Throws(new ElementNotFoundException(id));
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.CancelRequest(Guid.NewGuid().ToString()),
+        Throws.TypeOf<ElementNotFoundException>());
+        _requestStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Once);
+    }
+    [Test]
+    public void CancelRequest_IdIsNullOrEmpty_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _requestBusinessLogicContract.CancelRequest(null),
+        Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _requestBusinessLogicContract.CancelRequest(string.Empty),
+        Throws.TypeOf<ArgumentNullException>());
+        _requestStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Never); 
+    }
+    [Test]
+    public void CancelRequest_IdIsNotGuid_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _requestBusinessLogicContract.CancelRequest("id"),
+        Throws.TypeOf<ValidationException>());
+        _requestStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Never);
+    }
+    [Test]
+    public void CancelRequest_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _requestStorageContract.Setup(x =>
+        x.DelElement(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _requestBusinessLogicContract.CancelRequest(Guid.NewGuid().ToString()),
+        Throws.TypeOf<StorageException>());
+        _requestStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Once);
+    }
+}
--- a/SmallSoftwareProject/SmallSoftwareTests/BusinessLogicsContractsTests/SalaryBusinessLogicContractTests.cs
+++ b/SmallSoftwareProject/SmallSoftwareTests/BusinessLogicsContractsTests/SalaryBusinessLogicContractTests.cs
@@ -0,0 +1,460 @@
+using Microsoft.Extensions.Logging;
+using Moq;
+using SmallSoftwareBusinessLogic.Implementations;
+using SmallSoftwareContracts.DataModels;
+using SmallSoftwareContracts.Enums;
+using SmallSoftwareContracts.Exceptions;
+using SmallSoftwareContracts.StoragesContracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareTests.BusinessLogicsContractsTests;
+
+[TestFixture]
+internal class SalaryBusinessLogicContractTests
+{
+    private SalaryBusinessLogicContract _salaryBusinessLogicContract;
+    private Mock<ISalaryStorageContract> _salaryStorageContract;
+    private Mock<IRequestStorageContract> _requestStorageContract;
+    private Mock<IPostStorageContract> _postStorageContract;
+    private Mock<IWorkerStorageContract> _workerStorageContract;
+    [OneTimeSetUp]
+    public void OneTimeSetUp()
+    {
+        _salaryStorageContract = new Mock<ISalaryStorageContract>();
+        _requestStorageContract = new Mock<IRequestStorageContract>();
+        _postStorageContract = new Mock<IPostStorageContract>();
+        _workerStorageContract = new Mock<IWorkerStorageContract>();
+        _salaryBusinessLogicContract = new
+        SalaryBusinessLogicContract(_salaryStorageContract.Object,
+        _requestStorageContract.Object, _postStorageContract.Object,
+        _workerStorageContract.Object, new Mock<ILogger>().Object);
+    }
+    [SetUp]
+    public void SetUp()
+    {
+        _salaryStorageContract.Reset();
+        _requestStorageContract.Reset();
+        _postStorageContract.Reset();
+        _workerStorageContract.Reset();
+    }
+    [Test]
+    public void GetAllSalaries_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var startDate = DateTime.UtcNow;
+        var endDate = DateTime.UtcNow.AddDays(1);
+        var listOriginal = new List<SalaryDataModel>()
+        {
+            new(Guid.NewGuid().ToString(), DateTime.UtcNow, 10),
+            new(Guid.NewGuid().ToString(), DateTime.UtcNow.AddDays(1),
+            14),
+            new(Guid.NewGuid().ToString(), DateTime.UtcNow.AddDays(-1),
+            30),
+        };
+        _salaryStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>())).Returns(listOriginal);
+        //Act
+        var list =
+        _salaryBusinessLogicContract.GetAllSalariesByPeriod(startDate, endDate);
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Is.EquivalentTo(listOriginal));
+        _salaryStorageContract.Verify(x => x.GetList(startDate, endDate,
+        null), Times.Once);
+    }
+    [Test] 
+    public void GetAllSalaries_ReturnEmptyList_Test()
+    {
+        //Arrange
+        _salaryStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>())).Returns([]);
+        //Act
+        var list =
+        _salaryBusinessLogicContract.GetAllSalariesByPeriod(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1));
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(0));
+        _salaryStorageContract.Verify(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetAllSalaries_IncorrectDates_ThrowException_Test()
+    {
+        //Arrange
+        var dateTime = DateTime.UtcNow;
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.GetAllSalariesByPeriod(dateTime, dateTime),
+        Throws.TypeOf<IncorrectDatesException>());
+        Assert.That(() =>
+        _salaryBusinessLogicContract.GetAllSalariesByPeriod(dateTime,
+        dateTime.AddSeconds(-1)), Throws.TypeOf<IncorrectDatesException>());
+        _salaryStorageContract.Verify(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetAllSalaries_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.GetAllSalariesByPeriod(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1)), Throws.TypeOf<NullListException>());
+        _salaryStorageContract.Verify(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetAllSalaries_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _salaryStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.GetAllSalariesByPeriod(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1)), Throws.TypeOf<StorageException>());
+        _salaryStorageContract.Verify(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetAllSalariesByWorker_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var startDate = DateTime.UtcNow;
+        var endDate = DateTime.UtcNow.AddDays(1); 
+        var workerId = Guid.NewGuid().ToString();
+        var listOriginal = new List<SalaryDataModel>()
+        {
+            new(Guid.NewGuid().ToString(), DateTime.UtcNow, 10),
+            new(Guid.NewGuid().ToString(), DateTime.UtcNow.AddDays(1),
+            14),
+            new(Guid.NewGuid().ToString(), DateTime.UtcNow.AddDays(-1),
+            30),
+        };
+        _salaryStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>())).Returns(listOriginal);
+        //Act
+        var list =
+        _salaryBusinessLogicContract.GetAllSalariesByPeriodByWorker(startDate, endDate,
+        workerId);
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Is.EquivalentTo(listOriginal));
+        _salaryStorageContract.Verify(x => x.GetList(startDate, endDate,
+        workerId), Times.Once);
+    }
+    [Test]
+    public void GetAllSalariesByWorker_ReturnEmptyList_Test()
+    {
+        //Arrange
+        _salaryStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>())).Returns([]);
+        //Act
+        var list =
+        _salaryBusinessLogicContract.GetAllSalariesByPeriodByWorker(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1), Guid.NewGuid().ToString());
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(0));
+        _salaryStorageContract.Verify(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetAllSalariesByWorker_IncorrectDates_ThrowException_Test()
+    {
+        //Arrange
+        var dateTime = DateTime.UtcNow;
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.GetAllSalariesByPeriodByWorker(dateTime, dateTime,
+        Guid.NewGuid().ToString()), Throws.TypeOf<IncorrectDatesException>());
+        Assert.That(() =>
+        _salaryBusinessLogicContract.GetAllSalariesByPeriodByWorker(dateTime,
+        dateTime.AddSeconds(-1), Guid.NewGuid().ToString()),
+        Throws.TypeOf<IncorrectDatesException>());
+        _salaryStorageContract.Verify(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void
+    GetAllSalariesByWorker_WorkerIdIsNUllOrEmpty_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.GetAllSalariesByPeriodByWorker(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1), null), Throws.TypeOf<ArgumentNullException>()); 
+        Assert.That(() =>
+        _salaryBusinessLogicContract.GetAllSalariesByPeriodByWorker(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1), string.Empty),
+        Throws.TypeOf<ArgumentNullException>());
+        _salaryStorageContract.Verify(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetAllSalariesByWorker_WorkerIdIsNotGuid_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.GetAllSalariesByPeriodByWorker(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1), "workerId"), Throws.TypeOf<ValidationException>());
+        _salaryStorageContract.Verify(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetAllSalariesByWorker_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.GetAllSalariesByPeriodByWorker(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1), Guid.NewGuid().ToString()),
+        Throws.TypeOf<NullListException>());
+        _salaryStorageContract.Verify(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetAllSalariesByWorker_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _salaryStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.GetAllSalariesByPeriodByWorker(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1), Guid.NewGuid().ToString()),
+        Throws.TypeOf<StorageException>());
+        _salaryStorageContract.Verify(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void CalculateSalaryByMounth_CalculateSalary_Test()
+    {
+        //Arrange
+        var workerId = Guid.NewGuid().ToString();
+        var requestSum = 200.0;
+        var postSalary = 2000.0;
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>(), It.IsAny<string>()))
+        .Returns([new RequestDataModel(Guid.NewGuid().ToString(), workerId, Guid.NewGuid().ToString(), requestSum,  false, [])]);
+        _postStorageContract.Setup(x => x.GetElementById(It.IsAny<string>()))
+        .Returns(new PostDataModel(Guid.NewGuid().ToString(), "name",
+        PostType.SoftInstaller, postSalary, true, DateTime.UtcNow)); 
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()))
+        .Returns([new WorkerDataModel(workerId, "Test",
+        Guid.NewGuid().ToString(), DateTime.UtcNow, DateTime.UtcNow, false)]);
+        var sum = 0.0;
+        var expectedSum = postSalary + requestSum * 0.1;
+        _salaryStorageContract.Setup(x =>
+        x.AddElement(It.IsAny<SalaryDataModel>()))
+        .Callback((SalaryDataModel x) =>
+        {
+            sum = x.Salary;
+        });
+        //Act
+        _salaryBusinessLogicContract.CalculateSalaryByMonth(DateTime.UtcNow);
+        //Assert
+        Assert.That(sum, Is.EqualTo(expectedSum));
+    }
+    [Test]
+    public void CalculateSalaryByMounth_WithSeveralWorkers_Test()
+    {
+        //Arrange
+        var worker1Id = Guid.NewGuid().ToString();
+        var worker2Id = Guid.NewGuid().ToString();
+        var worker3Id = Guid.NewGuid().ToString();
+        var list = new List<WorkerDataModel>() {
+            new(worker1Id, "Test", Guid.NewGuid().ToString(),
+            DateTime.UtcNow, DateTime.UtcNow, false),
+            new(worker2Id, "Test", Guid.NewGuid().ToString(),
+            DateTime.UtcNow, DateTime.UtcNow, false),
+            new(worker3Id, "Test", Guid.NewGuid().ToString(),
+            DateTime.UtcNow, DateTime.UtcNow, false)
+        };  
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>(), It.IsAny<string>()))
+        .Returns([new RequestDataModel(Guid.NewGuid().ToString(),
+            worker1Id, Guid.NewGuid().ToString(), 1, false, []),
+            new RequestDataModel(Guid.NewGuid().ToString(), worker1Id, Guid.NewGuid().ToString(),
+            1, false, []),
+            new RequestDataModel(Guid.NewGuid().ToString(), worker2Id, Guid.NewGuid().ToString(),
+            1, false, []),
+            new RequestDataModel(Guid.NewGuid().ToString(), worker3Id, Guid.NewGuid().ToString(),
+            1, false, []),
+            new RequestDataModel(Guid.NewGuid().ToString(), worker3Id, Guid.NewGuid().ToString(),
+            1, false, [])]);
+        _postStorageContract.Setup(x => x.GetElementById(It.IsAny<string>()))
+        .Returns(new PostDataModel(Guid.NewGuid().ToString(), "name",
+        PostType.SoftInstaller, 2000, true, DateTime.UtcNow));
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()))
+        .Returns(list);
+        //Act
+        _salaryBusinessLogicContract.CalculateSalaryByMonth(DateTime.UtcNow);
+        //Assert
+        _salaryStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<SalaryDataModel>()), Times.Exactly(list.Count));
+    }
+    [Test] 
+    public void CalculateSalaryByMounth_WithoitRequestsByWorker_Test()
+    {
+        //Arrange
+        var postSalary = 2000.0;
+        var workerId = Guid.NewGuid().ToString();
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>(), It.IsAny<string>()))
+        .Returns([]);
+        _postStorageContract.Setup(x => x.GetElementById(It.IsAny<string>()))
+        .Returns(new PostDataModel(Guid.NewGuid().ToString(), "name",
+        PostType.SoftInstaller, postSalary, true, DateTime.UtcNow));
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()))
+        .Returns([new WorkerDataModel(workerId, "Test",
+Guid.NewGuid().ToString(), DateTime.UtcNow, DateTime.UtcNow, false)]);
+        var sum = 0.0;
+        var expectedSum = postSalary;
+        _salaryStorageContract.Setup(x =>
+        x.AddElement(It.IsAny<SalaryDataModel>()))
+        .Callback((SalaryDataModel x) =>
+        {
+            sum = x.Salary;
+        });
+        //Act
+        _salaryBusinessLogicContract.CalculateSalaryByMonth(DateTime.UtcNow);
+        //Assert
+        Assert.That(sum, Is.EqualTo(expectedSum));
+    }
+    [Test]
+    public void
+    CalculateSalaryByMounth_RequestStorageReturnNull_ThrowException_Test()
+    {
+        //Arrange
+        var workerId = Guid.NewGuid().ToString();
+        _postStorageContract.Setup(x => x.GetElementById(It.IsAny<string>()))
+        .Returns(new PostDataModel(Guid.NewGuid().ToString(), "name",
+        PostType.SoftInstaller, 2000, true, DateTime.UtcNow));
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()))
+        .Returns([new WorkerDataModel(workerId, "Test",
+Guid.NewGuid().ToString(), DateTime.UtcNow, DateTime.UtcNow, false)]);
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.CalculateSalaryByMonth(DateTime.UtcNow),
+        Throws.TypeOf<NullListException>());
+    }
+    [Test]
+    public void
+    CalculateSalaryByMounth_PostStorageReturnNull_ThrowException_Test()
+    {
+        //Arrange
+        var workerId = Guid.NewGuid().ToString();
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>(), It.IsAny<string>()))
+        .Returns([new RequestDataModel(Guid.NewGuid().ToString(), workerId, Guid.NewGuid().ToString(), 200, false, [])]); 
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()))
+        .Returns([new WorkerDataModel(workerId, "Test",
+        Guid.NewGuid().ToString(), DateTime.UtcNow, DateTime.UtcNow, false)]);
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.CalculateSalaryByMonth(DateTime.UtcNow),
+        Throws.TypeOf<NullListException>());
+    }
+    [Test]
+    public void
+    CalculateSalaryByMounth_WorkerStorageReturnNull_ThrowException_Test()
+    {
+        //Arrange
+        var workerId = Guid.NewGuid().ToString();
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>(), It.IsAny<string>()))
+        .Returns([new RequestDataModel(Guid.NewGuid().ToString(),
+        workerId, Guid.NewGuid().ToString(), 200,  false, [])]);
+        _postStorageContract.Setup(x => x.GetElementById(It.IsAny<string>()))
+        .Returns(new PostDataModel(Guid.NewGuid().ToString(), "name",
+        PostType.SoftInstaller, 2000, true, DateTime.UtcNow));
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.CalculateSalaryByMonth(DateTime.UtcNow),
+        Throws.TypeOf<NullListException>());
+    }
+    [Test]
+    public void
+    CalculateSalaryByMounth_RequestStorageThrowException_ThrowException_Test()
+    {
+        //Arrange
+        var workerId = Guid.NewGuid().ToString();
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>(), It.IsAny<string>()))
+        .Throws(new StorageException(new
+        InvalidOperationException()));
+        _postStorageContract.Setup(x => x.GetElementById(It.IsAny<string>()))
+        .Returns(new PostDataModel(Guid.NewGuid().ToString(), "name",
+        PostType.SoftInstaller, 2000, true, DateTime.UtcNow));
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()))
+        .Returns([new WorkerDataModel(workerId, "Test",
+Guid.NewGuid().ToString(), DateTime.UtcNow, DateTime.UtcNow, false)]);
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.CalculateSalaryByMonth(DateTime.UtcNow),
+        Throws.TypeOf<StorageException>());
+    }
+    [Test]
+    public void
+    CalculateSalaryByMounth_PostStorageThrowException_ThrowException_Test()
+    {
+        //Arrange
+        var workerId = Guid.NewGuid().ToString(); 
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>(), It.IsAny<string>()))
+        .Returns([new RequestDataModel(Guid.NewGuid().ToString(),
+        workerId, Guid.NewGuid().ToString(), 200, false, [])]);
+        _postStorageContract.Setup(x => x.GetElementById(It.IsAny<string>()))
+        .Throws(new StorageException(new
+        InvalidOperationException()));
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()))
+        .Returns([new WorkerDataModel(workerId, "Test",
+Guid.NewGuid().ToString(), DateTime.UtcNow, DateTime.UtcNow, false)]);
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.CalculateSalaryByMonth(DateTime.UtcNow),
+        Throws.TypeOf<StorageException>());
+    }
+    [Test]
+    public void
+    CalculateSalaryByMounth_WorkerStorageThrowException_ThrowException_Test()
+    {
+        //Arrange
+        var workerId = Guid.NewGuid().ToString();
+        _requestStorageContract.Setup(x => x.GetList(It.IsAny<DateTime>(),
+        It.IsAny<DateTime>(), It.IsAny<string>(), It.IsAny<string>()))
+        .Returns([new RequestDataModel(Guid.NewGuid().ToString(), workerId, Guid.NewGuid().ToString(), 200, false, [])]);
+        _postStorageContract.Setup(x => x.GetElementById(It.IsAny<string>()))
+        .Returns(new PostDataModel(Guid.NewGuid().ToString(), "name",
+        PostType.SoftInstaller, 2000, true, DateTime.UtcNow));
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()))
+        .Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _salaryBusinessLogicContract.CalculateSalaryByMonth(DateTime.UtcNow),
+        Throws.TypeOf<StorageException>());
+    }
+}
+
--- a/SmallSoftwareProject/SmallSoftwareTests/BusinessLogicsContractsTests/SoftwareBusinessLogicContractTests.cs
+++ b/SmallSoftwareProject/SmallSoftwareTests/BusinessLogicsContractsTests/SoftwareBusinessLogicContractTests.cs
@@ -0,0 +1,620 @@
+using Microsoft.Extensions.Logging;
+using Moq;
+using SmallSoftwareBusinessLogic.Implementations;
+using SmallSoftwareContracts.DataModels;
+using SmallSoftwareContracts.Enums;
+using SmallSoftwareContracts.Exceptions;
+using SmallSoftwareContracts.StoragesContracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using static NUnit.Framework.Internal.OSPlatform;
+
+namespace SmallSoftwareTests.BusinessLogicsContractsTests;
+
+[TestFixture]
+internal class SoftwareBusinessLogicContractTests
+{
+    private SoftwareBusinessLogicContract _softwareBusinessLogicContract;
+    private Mock<ISoftwareStorageContract> _softwareStorageContract;
+    [OneTimeSetUp]
+    public void OneTimeSetUp()
+    {
+        _softwareStorageContract = new Mock<ISoftwareStorageContract>();
+        _softwareBusinessLogicContract = new
+        SoftwareBusinessLogicContract(_softwareStorageContract.Object, new
+        Mock<ILogger>().Object);
+    }
+    [SetUp]
+    public void SetUp()
+    {
+        _softwareStorageContract.Reset();
+    } 
+    [Test]
+    public void GetAllSoftwares_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var listOriginal = new List<SoftwareDataModel>()
+        {
+            new(Guid.NewGuid().ToString(), "name 1", SoftwareType.Windows, Guid.NewGuid().ToString(), 10, false),
+            new(Guid.NewGuid().ToString(), "name 2", SoftwareType.Windows, Guid.NewGuid().ToString(), 10, true),
+            new(Guid.NewGuid().ToString(), "name 3", SoftwareType.Windows, Guid.NewGuid().ToString(), 10, false),
+        };
+        _softwareStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>())).Returns(listOriginal);
+        //Act
+        var listOnlyActive =
+        _softwareBusinessLogicContract.GetAllSoftwares(true);
+        var list = _softwareBusinessLogicContract.GetAllSoftwares(false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null);
+            Assert.That(list, Is.Not.Null);
+            Assert.That(listOnlyActive, Is.EquivalentTo(listOriginal));
+            Assert.That(list, Is.EquivalentTo(listOriginal));
+        });
+        _softwareStorageContract.Verify(x => x.GetList(true, null),
+        Times.Once);
+        _softwareStorageContract.Verify(x => x.GetList(false, null),
+        Times.Once);
+    }
+    [Test]
+    public void GetAllSoftwares_ReturnEmptyList_Test()
+    {
+        //Arrange
+        _softwareStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>())).Returns([]);
+        //Act
+        var listOnlyActive =
+        _softwareBusinessLogicContract.GetAllSoftwares(true);
+        var list = _softwareBusinessLogicContract.GetAllSoftwares(false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null);
+            Assert.That(list, Is.Not.Null);
+            Assert.That(listOnlyActive, Has.Count.EqualTo(0));
+            Assert.That(list, Has.Count.EqualTo(0));
+        });
+        _softwareStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        null), Times.Exactly(2));
+    }
+    [Test]
+    public void GetAllSoftwares_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetAllSoftwares(It.IsAny<bool>()),
+        Throws.TypeOf<NullListException>()); 
+        _softwareStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetAllSoftwares_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _softwareStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetAllSoftwares(It.IsAny<bool>()),
+        Throws.TypeOf<StorageException>());
+        _softwareStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetAllSoftwaresByManufacturer_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var manufacturerId = Guid.NewGuid().ToString();
+        var listOriginal = new List<SoftwareDataModel>()
+        {
+        new(Guid.NewGuid().ToString(), "name 1",SoftwareType.Windows,
+        Guid.NewGuid().ToString(), 10, false),
+        new(Guid.NewGuid().ToString(), "name 2",
+        SoftwareType.Windows, Guid.NewGuid().ToString(), 10, true),
+        new(Guid.NewGuid().ToString(), "name 3",
+        SoftwareType.Windows, Guid.NewGuid().ToString(), 10, false),
+        };
+        _softwareStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>())).Returns(listOriginal);
+        //Act
+        var listOnlyActive =
+        _softwareBusinessLogicContract.GetAllSoftwaresByManufacturer(manufacturerId, true);
+        var list =
+        _softwareBusinessLogicContract.GetAllSoftwaresByManufacturer(manufacturerId,
+        false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null);
+            Assert.That(list, Is.Not.Null);
+            Assert.That(listOnlyActive, Is.EquivalentTo(listOriginal));
+            Assert.That(list, Is.EquivalentTo(listOriginal));
+        });
+        _softwareStorageContract.Verify(x => x.GetList(true, manufacturerId),
+        Times.Once);
+        _softwareStorageContract.Verify(x => x.GetList(false, manufacturerId),
+        Times.Once);
+    }
+    [Test]
+    public void GetAllSoftwaresByManufacturer_ReturnEmptyList_Test()
+    {
+        //Arrange
+        var manufacturerId = Guid.NewGuid().ToString();
+        _softwareStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>())).Returns([]);
+        //Act 
+        var listOnlyActive =
+        _softwareBusinessLogicContract.GetAllSoftwaresByManufacturer(manufacturerId, true);
+        var list =
+        _softwareBusinessLogicContract.GetAllSoftwaresByManufacturer(manufacturerId,
+        false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null);
+            Assert.That(list, Is.Not.Null);
+            Assert.That(listOnlyActive, Has.Count.EqualTo(0));
+            Assert.That(list, Has.Count.EqualTo(0));
+        });
+        _softwareStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        manufacturerId), Times.Exactly(2));
+    }
+    [Test]
+    public void
+    GetAllSoftwaresByManufacturer_ManufacturerIdIsNullOrEmpty_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetAllSoftwaresByManufacturer(null,
+        It.IsAny<bool>()), Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetAllSoftwaresByManufacturer(string.Empty,
+        It.IsAny<bool>()), Throws.TypeOf<ArgumentNullException>());
+        _softwareStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void
+    GetAllSoftwaresByManufacturer_ManufacturerIdIsNotGuid_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetAllSoftwaresByManufacturer("manufacturerId",
+        It.IsAny<bool>()), Throws.TypeOf<ValidationException>());
+        _softwareStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetAllSoftwaresByManufacturer_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetAllSoftwaresByManufacturer(Guid.NewGuid().ToString(), It.IsAny<bool>()), Throws.TypeOf<NullListException>());
+        _softwareStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void
+    GetAllSoftwaresByManufacturer_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _softwareStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert 
+    Assert.That(() =>
+    _softwareBusinessLogicContract.GetAllSoftwaresByManufacturer(Guid.NewGuid().ToString(), It.IsAny<bool>()), Throws.TypeOf<StorageException>());
+        _softwareStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetSoftwareHistoryBySoftware_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var softwareId = Guid.NewGuid().ToString();
+        var listOriginal = new List<SoftwareHistoryDataModel>()
+{
+new(Guid.NewGuid().ToString(), 10),
+new(Guid.NewGuid().ToString(), 15),
+new(Guid.NewGuid().ToString(), 10),
+};
+        _softwareStorageContract.Setup(x =>
+        x.GetHistoryBySoftwareId(It.IsAny<string>())).Returns(listOriginal);
+        //Act
+        var list =
+        _softwareBusinessLogicContract.GetSoftwareHistoryBySoftware(softwareId);
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Is.EquivalentTo(listOriginal));
+        _softwareStorageContract.Verify(x =>
+        x.GetHistoryBySoftwareId(softwareId), Times.Once);
+    }
+    [Test]
+    public void GetSoftwareHistoryBySoftware_ReturnEmptyList_Test()
+    {
+        //Arrange
+        _softwareStorageContract.Setup(x =>
+        x.GetHistoryBySoftwareId(It.IsAny<string>())).Returns([]);
+        //Act
+        var list =
+        _softwareBusinessLogicContract.GetSoftwareHistoryBySoftware(Guid.NewGuid().ToString(
+        ));
+        //Assert
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(0));
+        _softwareStorageContract.Verify(x =>
+        x.GetHistoryBySoftwareId(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void
+    GetSoftwareHistoryBySoftware_SoftwareIdIsNullOrEmpty_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetSoftwareHistoryBySoftware(null),
+        Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetSoftwareHistoryBySoftware(string.Empty),
+        Throws.TypeOf<ArgumentNullException>());
+        _softwareStorageContract.Verify(x =>
+        x.GetHistoryBySoftwareId(It.IsAny<string>()), Times.Never);
+    }
+    [Test] 
+    public void
+    GetSoftwareHistoryBySoftware_SoftwareIdIsNotGuid_ThrowException_Test()
+        {
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetSoftwareHistoryBySoftware("softwareId"),
+        Throws.TypeOf<ValidationException>());
+        _softwareStorageContract.Verify(x =>
+        x.GetHistoryBySoftwareId(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetSoftwareHistoryBySoftware_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetSoftwareHistoryBySoftware(Guid.NewGuid().ToString(
+        )), Throws.TypeOf<NullListException>());
+        _softwareStorageContract.Verify(x =>
+        x.GetHistoryBySoftwareId(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void
+    GetSoftwareHistoryBySoftware_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _softwareStorageContract.Setup(x =>
+        x.GetHistoryBySoftwareId(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetSoftwareHistoryBySoftware(Guid.NewGuid().ToString(
+        )), Throws.TypeOf<StorageException>());
+        _softwareStorageContract.Verify(x =>
+        x.GetHistoryBySoftwareId(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetSoftwareByData_GetById_ReturnRecord_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        var record = new SoftwareDataModel(id, "name", SoftwareType.Windows,
+        Guid.NewGuid().ToString(), 10, false);
+        _softwareStorageContract.Setup(x =>
+        x.GetElementById(id)).Returns(record);
+        //Act
+        var element = _softwareBusinessLogicContract.GetSoftwareByData(id);
+        //Assert
+        Assert.That(element, Is.Not.Null);
+        Assert.That(element.Id, Is.EqualTo(id));
+        _softwareStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetSoftwareByData_GetByName_ReturnRecord_Test()
+    {
+        //Arrange
+        var name = "name";
+        var record = new SoftwareDataModel(Guid.NewGuid().ToString(), name,
+        SoftwareType.Windows, Guid.NewGuid().ToString(), 10, false); 
+        _softwareStorageContract.Setup(x =>
+        x.GetElementByName(name)).Returns(record);
+        //Act
+        var element = _softwareBusinessLogicContract.GetSoftwareByData(name);
+        //Assert
+        Assert.That(element, Is.Not.Null);
+        Assert.That(element.SoftwareName, Is.EqualTo(name));
+        _softwareStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetSoftwareByData_EmptyData_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetSoftwareByData(null),
+        Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetSoftwareByData(string.Empty),
+        Throws.TypeOf<ArgumentNullException>());
+        _softwareStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Never);
+        _softwareStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetSoftwareByData_GetById_NotFoundRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetSoftwareByData(Guid.NewGuid().ToString()),
+        Throws.TypeOf<ElementNotFoundException>());
+        _softwareStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetSoftwareByData_GetByName_NotFoundRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetSoftwareByData("name"),
+        Throws.TypeOf<ElementNotFoundException>());
+        _softwareStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetSoftwareByData_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _softwareStorageContract.Setup(x =>
+        x.GetElementById(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        _softwareStorageContract.Setup(x =>
+        x.GetElementByName(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetSoftwareByData(Guid.NewGuid().ToString()),
+        Throws.TypeOf<StorageException>()); 
+        Assert.That(() =>
+        _softwareBusinessLogicContract.GetSoftwareByData("name"),
+        Throws.TypeOf<StorageException>());
+        _softwareStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Once);
+        _softwareStorageContract.Verify(x =>
+        x.GetElementByName(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void InsertSoftware_CorrectRecord_Test()
+    {
+        //Arrange
+        var flag = false;
+        var record = new SoftwareDataModel(Guid.NewGuid().ToString(), "name",
+        SoftwareType.Windows, Guid.NewGuid().ToString(), 10, false);
+        _softwareStorageContract.Setup(x =>
+        x.AddElement(It.IsAny<SoftwareDataModel>()))
+        .Callback((SoftwareDataModel x) =>
+        {
+            flag = x.Id == record.Id && x.SoftwareName ==
+    record.SoftwareName && x.SoftwareType == record.SoftwareType &&
+    x.ManufacturerId == record.ManufacturerId && x.Price ==
+    record.Price && x.IsDeleted == record.IsDeleted;
+        });
+        //Act
+        _softwareBusinessLogicContract.InsertSoftware(record);
+        //Assert
+        _softwareStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<SoftwareDataModel>()), Times.Once);
+        Assert.That(flag);
+    }
+    [Test]
+    public void InsertSoftware_RecordWithExistsData_ThrowException_Test()
+    {
+        //Arrange
+        _softwareStorageContract.Setup(x =>
+        x.AddElement(It.IsAny<SoftwareDataModel>())).Throws(new
+        ElementExistsException("Data", "Data"));
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.InsertSoftware(new(Guid.NewGuid().ToString(),
+        "name", SoftwareType.Windows, Guid.NewGuid().ToString(), 10, false)),
+        Throws.TypeOf<ElementExistsException>());
+        _softwareStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<SoftwareDataModel>()), Times.Once);
+    }
+    [Test]
+    public void InsertSoftware_NullRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _softwareBusinessLogicContract.InsertSoftware(null),
+        Throws.TypeOf<ArgumentNullException>());
+        _softwareStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<SoftwareDataModel>()), Times.Never);
+    }
+    [Test]
+    public void InsertSoftware_InvalidRecord_ThrowException_Test()
+    {
+        //Act&Assert 
+        Assert.That(() => _softwareBusinessLogicContract.InsertSoftware(new
+        SoftwareDataModel("id", "name", SoftwareType.Windows, Guid.NewGuid().ToString(),
+        10, false)), Throws.TypeOf<ValidationException>());
+        _softwareStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<SoftwareDataModel>()), Times.Never);
+    }
+    [Test]
+    public void InsertSoftware_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _softwareStorageContract.Setup(x =>
+        x.AddElement(It.IsAny<SoftwareDataModel>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.InsertSoftware(new(Guid.NewGuid().ToString(),
+        "name", SoftwareType.Windows, Guid.NewGuid().ToString(), 10, false)),
+        Throws.TypeOf<StorageException>());
+        _softwareStorageContract.Verify(x =>
+        x.AddElement(It.IsAny<SoftwareDataModel>()), Times.Once);
+    }
+    [Test]
+    public void UpdateSoftware_CorrectRecord_Test()
+    {
+        //Arrange
+        var flag = false;
+        var record = new SoftwareDataModel(Guid.NewGuid().ToString(), "name",
+        SoftwareType.Windows, Guid.NewGuid().ToString(), 10, false);
+        _softwareStorageContract.Setup(x =>
+        x.UpdElement(It.IsAny<SoftwareDataModel>()))
+        .Callback((SoftwareDataModel x) =>
+        {
+            flag = x.Id == record.Id && x.SoftwareName ==
+    record.SoftwareName && x.SoftwareType == record.SoftwareType &&
+    x.ManufacturerId == record.ManufacturerId && x.Price ==
+    record.Price && x.IsDeleted == record.IsDeleted;
+        });
+        //Act
+        _softwareBusinessLogicContract.UpdateSoftware(record);
+        //Assert
+        _softwareStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<SoftwareDataModel>()), Times.Once);
+        Assert.That(flag);
+    }
+    [Test]
+    public void UpdateSoftware_RecordWithIncorrectData_ThrowException_Test()
+    {
+        //Arrange
+        _softwareStorageContract.Setup(x =>
+        x.UpdElement(It.IsAny<SoftwareDataModel>())).Throws(new
+        ElementNotFoundException(""));
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.UpdateSoftware(new(Guid.NewGuid().ToString(),
+        "name", SoftwareType.Windows, Guid.NewGuid().ToString(), 10, false)),
+        Throws.TypeOf<ElementNotFoundException>());
+        _softwareStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<SoftwareDataModel>()), Times.Once);
+    }
+    [Test]
+ 
+    public void UpdateSoftware_RecordWithExistsData_ThrowException_Test()
+    {
+        //Arrange
+        _softwareStorageContract.Setup(x =>
+        x.UpdElement(It.IsAny<SoftwareDataModel>())).Throws(new
+        ElementExistsException("Data", "Data"));
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.UpdateSoftware(new(Guid.NewGuid().ToString(),
+        "anme", SoftwareType.Windows, Guid.NewGuid().ToString(), 10, false)),
+        Throws.TypeOf<ElementExistsException>());
+        _softwareStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<SoftwareDataModel>()), Times.Once);
+    }
+    [Test]
+    public void UpdateSoftware_NullRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _softwareBusinessLogicContract.UpdateSoftware(null),
+        Throws.TypeOf<ArgumentNullException>());
+        _softwareStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<SoftwareDataModel>()), Times.Never);
+    }
+    [Test]
+    public void UpdateSoftware_InvalidRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _softwareBusinessLogicContract.UpdateSoftware(new
+        SoftwareDataModel("id", "name", SoftwareType.Windows, Guid.NewGuid().ToString(),
+        10, false)), Throws.TypeOf<ValidationException>());
+        _softwareStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<SoftwareDataModel>()), Times.Never);
+    }
+    [Test]
+    public void UpdateSoftware_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _softwareStorageContract.Setup(x =>
+        x.UpdElement(It.IsAny<SoftwareDataModel>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.UpdateSoftware(new(Guid.NewGuid().ToString(),
+        "name", SoftwareType.Windows, Guid.NewGuid().ToString(), 10, false)),
+        Throws.TypeOf<StorageException>());
+        _softwareStorageContract.Verify(x =>
+        x.UpdElement(It.IsAny<SoftwareDataModel>()), Times.Once);
+    }
+    [Test]
+    public void DeleteSoftware_CorrectRecord_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        var flag = false;
+        _softwareStorageContract.Setup(x => x.DelElement(It.Is((string x) => x
+        == id))).Callback(() => { flag = true; });
+        //Act
+        _softwareBusinessLogicContract.DeleteSoftware(id);
+        //Assert 
+        _softwareStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Once);
+        Assert.That(flag);
+    }
+    [Test]
+    public void DeleteSoftware_RecordWithIncorrectId_ThrowException_Test()
+    {
+        //Arrange
+        var id = Guid.NewGuid().ToString();
+        _softwareStorageContract.Setup(x =>
+        x.DelElement(It.IsAny<string>())).Throws(new ElementNotFoundException(id));
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.DeleteSoftware(Guid.NewGuid().ToString()),
+        Throws.TypeOf<ElementNotFoundException>());
+        _softwareStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Once);
+    }
+    [Test]
+    public void DeleteSoftware_IdIsNullOrEmpty_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _softwareBusinessLogicContract.DeleteSoftware(null),
+        Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _softwareBusinessLogicContract.DeleteSoftware(string.Empty),
+        Throws.TypeOf<ArgumentNullException>());
+        _softwareStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Never);
+    }
+    [Test]
+    public void DeleteSoftware_IdIsNotGuid_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _softwareBusinessLogicContract.DeleteSoftware("id"),
+        Throws.TypeOf<ValidationException>());
+        _softwareStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Never);
+    }
+    [Test]
+    public void DeleteSoftware_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _softwareStorageContract.Setup(x =>
+        x.DelElement(It.IsAny<string>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _softwareBusinessLogicContract.DeleteSoftware(Guid.NewGuid().ToString()),
+        Throws.TypeOf<StorageException>());
+        _softwareStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+        Times.Once);
+    }
+}
+
--- a/SmallSoftwareProject/SmallSoftwareTests/BusinessLogicsContractsTests/WorkerBusinessLogicContractTests.cs
+++ b/SmallSoftwareProject/SmallSoftwareTests/BusinessLogicsContractsTests/WorkerBusinessLogicContractTests.cs
@@ -0,0 +1,766 @@
+using Microsoft.Extensions.Logging;
+using Moq;
+using SmallSoftwareBusinessLogic.Implementations;
+using SmallSoftwareContracts.DataModels;
+using SmallSoftwareContracts.Exceptions;
+using SmallSoftwareContracts.StoragesContracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SmallSoftwareTests.BusinessLogicsContractsTests;
+
+[TestFixture]
+internal class WorkerBusinessLogicContractTests
+{
+    private WorkerBusinessLogicContract _workerBusinessLogicContract;
+    private Mock<IWorkerStorageContract> _workerStorageContract;
+    [OneTimeSetUp]
+    public void OneTimeSetUp()
+    {
+        _workerStorageContract = new Mock<IWorkerStorageContract>();
+        _workerBusinessLogicContract = new
+        WorkerBusinessLogicContract(_workerStorageContract.Object, new
+        Mock<ILogger>().Object);
+    }
+    [SetUp]
+    public void SetUp()
+    {
+        _workerStorageContract.Reset();
+    }
+    [Test]
+    public void GetAllWorkers_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var listOriginal = new List<WorkerDataModel>() 
+    {
+            new(Guid.NewGuid().ToString(), "fio 1",
+            Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+            false),
+            new(Guid.NewGuid().ToString(), "fio 2",
+            Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+            true),
+            new(Guid.NewGuid().ToString(), "fio 3",
+            Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+            false),
+    };
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>())).Returns(listOriginal);
+        //Act
+        var listOnlyActive =
+        _workerBusinessLogicContract.GetAllWorkers(true);
+        var list = _workerBusinessLogicContract.GetAllWorkers(false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null);
+            Assert.That(list, Is.Not.Null);
+            Assert.That(listOnlyActive, Is.EquivalentTo(listOriginal));
+            Assert.That(list, Is.EquivalentTo(listOriginal));
+        });
+        _workerStorageContract.Verify(x => x.GetList(true, null, null, null,
+        null, null), Times.Once);
+        _workerStorageContract.Verify(x => x.GetList(false, null, null, null,
+        null, null), Times.Once);
+    }
+    [Test]
+    public void GetAllWorkers_ReturnEmptyList_Test()
+    {
+        //Arrange
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>())).Returns([]);
+        //Act
+        var listOnlyActive =
+        _workerBusinessLogicContract.GetAllWorkers(true);
+        var list = _workerBusinessLogicContract.GetAllWorkers(false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null);
+            Assert.That(list, Is.Not.Null);
+            Assert.That(listOnlyActive, Has.Count.EqualTo(0));
+            Assert.That(list, Has.Count.EqualTo(0));
+        });
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(), null,
+        null, null, null, null), Times.Exactly(2));
+    }
+    [Test]
+    public void GetAllWorkers_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkers(It.IsAny<bool>()),
+        Throws.TypeOf<NullListException>()); 
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Once);
+    }
+    [Test]
+    public void GetAllWorkers_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkers(It.IsAny<bool>()),
+        Throws.TypeOf<StorageException>());
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(), null,
+        null, null, null, null), Times.Once);
+    }
+    [Test]
+    public void GetAllWorkersByPost_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var postId = Guid.NewGuid().ToString();
+        var listOriginal = new List<WorkerDataModel>()
+{
+new(Guid.NewGuid().ToString(), "fio 1",
+Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+false),
+new(Guid.NewGuid().ToString(), "fio 2",
+Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+true),
+new(Guid.NewGuid().ToString(), "fio 3",
+Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+false),
+};
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>())).Returns(listOriginal);
+        //Act
+        var listOnlyActive =
+        _workerBusinessLogicContract.GetAllWorkersByPost(postId, true);
+        var list = _workerBusinessLogicContract.GetAllWorkersByPost(postId,
+        false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null);
+            Assert.That(list, Is.Not.Null);
+            Assert.That(listOnlyActive, Is.EquivalentTo(listOriginal));
+            Assert.That(list, Is.EquivalentTo(listOriginal));
+        });
+        _workerStorageContract.Verify(x => x.GetList(true, postId, null,
+        null, null, null), Times.Once);
+        _workerStorageContract.Verify(x => x.GetList(false, postId, null,
+        null, null, null), Times.Once);
+    }
+    [Test]
+    public void GetAllWorkersByPost_ReturnEmptyList_Test()
+    {
+        //Arrange 
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>())).Returns([]);
+        //Act
+        var listOnlyActive =
+        _workerBusinessLogicContract.GetAllWorkersByPost(Guid.NewGuid().ToString(),
+        true);
+        var list =
+        _workerBusinessLogicContract.GetAllWorkersByPost(Guid.NewGuid().ToString(),
+        false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null);
+            Assert.That(list, Is.Not.Null);
+            Assert.That(listOnlyActive, Has.Count.EqualTo(0));
+            Assert.That(list, Has.Count.EqualTo(0));
+        });
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Exactly(2));
+    }
+    [Test]
+    public void GetAllWorkersByPost_PostIdIsNullOrEmpty_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkersByPost(null, It.IsAny<bool>()),
+        Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkersByPost(string.Empty, It.IsAny<bool>()),
+        Throws.TypeOf<ArgumentNullException>());
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Never);
+    }
+    [Test]
+    public void GetAllWorkersByPost_PostIdIsNotGuid_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkersByPost("postId", It.IsAny<bool>()),
+        Throws.TypeOf<ValidationException>());
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Never);
+    }
+    [Test]
+    public void GetAllWorkersByPost_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkersByPost(Guid.NewGuid().ToString(),
+        It.IsAny<bool>()), Throws.TypeOf<NullListException>());
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Once);
+    }
+    [Test]
+    public void GetAllWorkersByPost_StorageThrowError_ThrowException_Test() 
+    {
+        //Arrange
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkersByPost(Guid.NewGuid().ToString(),
+        It.IsAny<bool>()), Throws.TypeOf<StorageException>());
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Once);
+    }
+    [Test]
+    public void GetAllWorkersByBirthDate_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var date = DateTime.UtcNow;
+        var listOriginal = new List<WorkerDataModel>()
+        {
+            new(Guid.NewGuid().ToString(), "fio 1",
+            Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+            false),
+            new(Guid.NewGuid().ToString(), "fio 2",
+            Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+            true),
+            new(Guid.NewGuid().ToString(), "fio 3",
+            Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+            false),
+        };
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>())).Returns(listOriginal);
+        //Act
+        var listOnlyActive =
+        _workerBusinessLogicContract.GetAllWorkersByBirthDate(date, date.AddDays(1),
+        true);
+        var list =
+        _workerBusinessLogicContract.GetAllWorkersByBirthDate(date, date.AddDays(1),
+        false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null);
+            Assert.That(list, Is.Not.Null);
+            Assert.That(listOnlyActive, Is.EquivalentTo(listOriginal));
+            Assert.That(list, Is.EquivalentTo(listOriginal));
+        });
+        _workerStorageContract.Verify(x => x.GetList(true, null, date,
+        date.AddDays(1), null, null), Times.Once);
+        _workerStorageContract.Verify(x => x.GetList(false, null, date,
+        date.AddDays(1), null, null), Times.Once);
+    }
+    [Test]
+    public void GetAllWorkersByBirthDate_ReturnEmptyList_Test()
+    {
+        //Arrange
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>())).Returns([]);
+        //Act 
+        var listOnlyActive =
+        _workerBusinessLogicContract.GetAllWorkersByBirthDate(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1), true);
+        var list = _workerBusinessLogicContract.GetAllWorkers(false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null);
+            Assert.That(list, Is.Not.Null);
+            Assert.That(listOnlyActive, Has.Count.EqualTo(0));
+            Assert.That(list, Has.Count.EqualTo(0));
+        });
+        _workerStorageContract.Verify(x => x.GetList(true, null,
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>(), null, null), Times.Once);
+        _workerStorageContract.Verify(x => x.GetList(false, null,
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>(), null, null), Times.Once);
+    }
+    [Test]
+    public void GetAllWorkersByBirthDate_IncorrectDates_ThrowException_Test()
+    {
+        //Arrange
+        var date = DateTime.UtcNow;
+        //Act&Assert
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkersByBirthDate(date, date,
+        It.IsAny<bool>()), Throws.TypeOf<IncorrectDatesException>());
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkersByBirthDate(date, date.AddSeconds(-1),
+        It.IsAny<bool>()), Throws.TypeOf<IncorrectDatesException>());
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Never);
+    }
+    [Test]
+    public void GetAllWorkersByBirthDate_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkersByBirthDate(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1), It.IsAny<bool>()),
+        Throws.TypeOf<NullListException>());
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Once);
+    }
+    [Test]
+    public void
+    GetAllWorkersByBirthDate_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkersByBirthDate(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1), It.IsAny<bool>()),
+            Throws.TypeOf<StorageException>()); 
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Once);
+    }
+    [Test]
+    public void GetAllWorkersByEmploymentDate_ReturnListOfRecords_Test()
+    {
+        //Arrange
+        var date = DateTime.UtcNow;
+        var listOriginal = new List<WorkerDataModel>()
+{
+new(Guid.NewGuid().ToString(), "fio 1",
+Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+false),
+new(Guid.NewGuid().ToString(), "fio 2",
+Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+true),
+new(Guid.NewGuid().ToString(), "fio 3",
+Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+false),
+};
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>())).Returns(listOriginal);
+        //Act
+        var listOnlyActive =
+        _workerBusinessLogicContract.GetAllWorkersByEmploymentDate(date, date.AddDays(1),
+        true);
+        var list =
+        _workerBusinessLogicContract.GetAllWorkersByEmploymentDate(date, date.AddDays(1),
+        false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null);
+            Assert.That(list, Is.Not.Null);
+            Assert.That(listOnlyActive, Is.EquivalentTo(listOriginal));
+            Assert.That(list, Is.EquivalentTo(listOriginal));
+        });
+        _workerStorageContract.Verify(x => x.GetList(true, null, null, null,
+        date, date.AddDays(1)), Times.Once);
+        _workerStorageContract.Verify(x => x.GetList(false, null, null, null,
+        date, date.AddDays(1)), Times.Once);
+    }
+    [Test]
+    public void GetAllWorkersByEmploymentDate_ReturnEmptyList_Test()
+    {
+        //Arrange
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>())).Returns([]);
+        //Act
+        var listOnlyActive =
+        _workerBusinessLogicContract.GetAllWorkersByEmploymentDate(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1), true);
+        var list =
+        _workerBusinessLogicContract.GetAllWorkersByEmploymentDate(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1), false);
+        //Assert
+        Assert.Multiple(() =>
+        {
+            Assert.That(listOnlyActive, Is.Not.Null); 
+            Assert.That(list, Is.Not.Null);
+            Assert.That(listOnlyActive, Has.Count.EqualTo(0));
+            Assert.That(list, Has.Count.EqualTo(0));
+        });
+        _workerStorageContract.Verify(x => x.GetList(true, null, null, null,
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Once);
+        _workerStorageContract.Verify(x => x.GetList(false, null, null, null,
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Once);
+    }
+    [Test]
+    public void
+    GetAllWorkersByEmploymentDate_IncorrectDates_ThrowException_Test()
+    {
+        //Arrange
+        var date = DateTime.UtcNow;
+        //Act&Assert
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkersByEmploymentDate(date, date,
+        It.IsAny<bool>()), Throws.TypeOf<IncorrectDatesException>());
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkersByEmploymentDate(date,
+        date.AddSeconds(-1), It.IsAny<bool>()),
+        Throws.TypeOf<IncorrectDatesException>());
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Never);
+    }
+    [Test]
+    public void GetAllWorkersByEmploymentDate_ReturnNull_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkersByEmploymentDate(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1), It.IsAny<bool>()),
+        Throws.TypeOf<NullListException>());
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Once);
+    }
+    [Test]
+    public void
+    GetAllWorkersByEmploymentDate_StorageThrowError_ThrowException_Test()
+    {
+        //Arrange
+        _workerStorageContract.Setup(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>())).Throws(new StorageException(new
+        InvalidOperationException()));
+        //Act&Assert
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetAllWorkersByEmploymentDate(DateTime.UtcNow,
+        DateTime.UtcNow.AddDays(1), It.IsAny<bool>()),
+        Throws.TypeOf<StorageException>());
+        _workerStorageContract.Verify(x => x.GetList(It.IsAny<bool>(),
+        It.IsAny<string?>(), It.IsAny<DateTime?>(), It.IsAny<DateTime?>(),
+        It.IsAny<DateTime?>(), It.IsAny<DateTime?>()), Times.Once);
+    }
+    [Test]
+    public void GetWorkerByData_GetById_ReturnRecord_Test()
+    { 
+    //Arrange
+        var id = Guid.NewGuid().ToString();
+        var record = new WorkerDataModel(id, "fio",
+        Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+        false);
+        _workerStorageContract.Setup(x =>
+        x.GetElementById(id)).Returns(record);
+        //Act
+        var element = _workerBusinessLogicContract.GetWorkerByData(id);
+        //Assert
+        Assert.That(element, Is.Not.Null);
+        Assert.That(element.Id, Is.EqualTo(id));
+        _workerStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetWorkerByData_GetByFio_ReturnRecord_Test()
+    {
+        //Arrange
+        var fio = "fio";
+        var record = new WorkerDataModel(Guid.NewGuid().ToString(), fio,
+        Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+        false);
+        _workerStorageContract.Setup(x =>
+        x.GetElementByFIO(fio)).Returns(record);
+        //Act
+        var element = _workerBusinessLogicContract.GetWorkerByData(fio);
+        //Assert
+        Assert.That(element, Is.Not.Null);
+        Assert.That(element.FIO, Is.EqualTo(fio));
+        _workerStorageContract.Verify(x =>
+        x.GetElementByFIO(It.IsAny<string>()), Times.Once);
+    }
+    [Test]
+    public void GetWorkerByData_EmptyData_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() => _workerBusinessLogicContract.GetWorkerByData(null),
+        Throws.TypeOf<ArgumentNullException>());
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetWorkerByData(string.Empty),
+        Throws.TypeOf<ArgumentNullException>());
+        _workerStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Never);
+        _workerStorageContract.Verify(x =>
+        x.GetElementByFIO(It.IsAny<string>()), Times.Never);
+    }
+    [Test]
+    public void GetWorkerByData_GetById_NotFoundRecord_ThrowException_Test()
+    {
+        //Act&Assert
+        Assert.That(() =>
+        _workerBusinessLogicContract.GetWorkerByData(Guid.NewGuid().ToString()),
+        Throws.TypeOf<ElementNotFoundException>());
+        _workerStorageContract.Verify(x =>
+        x.GetElementById(It.IsAny<string>()), Times.Once);
+        _workerStorageContract.Verify(x =>
+        x.GetElementByFIO(It.IsAny<string>()), Times.Never);
+    }
+[Test] 
+public void GetWorkerByData_GetByFio_NotFoundRecord_ThrowException_Test()
+{
+    //Act&Assert
+    Assert.That(() =>
+    _workerBusinessLogicContract.GetWorkerByData("fio"),
+    Throws.TypeOf<ElementNotFoundException>());
+    _workerStorageContract.Verify(x =>
+    x.GetElementById(It.IsAny<string>()), Times.Never);
+    _workerStorageContract.Verify(x =>
+    x.GetElementByFIO(It.IsAny<string>()), Times.Once);
+}
+[Test]
+public void GetWorkerByData_StorageThrowError_ThrowException_Test()
+{
+    //Arrange
+    _workerStorageContract.Setup(x =>
+    x.GetElementById(It.IsAny<string>())).Throws(new StorageException(new
+    InvalidOperationException()));
+    _workerStorageContract.Setup(x =>
+    x.GetElementByFIO(It.IsAny<string>())).Throws(new StorageException(new
+    InvalidOperationException()));
+    //Act&Assert
+    Assert.That(() =>
+    _workerBusinessLogicContract.GetWorkerByData(Guid.NewGuid().ToString()),
+    Throws.TypeOf<StorageException>());
+    Assert.That(() =>
+    _workerBusinessLogicContract.GetWorkerByData("fio"),
+    Throws.TypeOf<StorageException>());
+    _workerStorageContract.Verify(x =>
+    x.GetElementById(It.IsAny<string>()), Times.Once);
+    _workerStorageContract.Verify(x =>
+    x.GetElementByFIO(It.IsAny<string>()), Times.Once);
+}
+[Test]
+public void InsertWorker_CorrectRecord_Test()
+{
+    //Arrange
+    var flag = false;
+    var record = new WorkerDataModel(Guid.NewGuid().ToString(), "fio",
+    Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+    false);
+    _workerStorageContract.Setup(x =>
+    x.AddElement(It.IsAny<WorkerDataModel>()))
+    .Callback((WorkerDataModel x) =>
+    {
+        flag = x.Id == record.Id && x.FIO == record.FIO &&
+    x.PostId == record.PostId && x.BirthDate == record.BirthDate &&
+    x.EmploymentDate == record.EmploymentDate &&
+    x.IsDeleted == record.IsDeleted;
+    });
+    //Act
+    _workerBusinessLogicContract.InsertWorker(record);
+    //Assert
+    _workerStorageContract.Verify(x =>
+    x.AddElement(It.IsAny<WorkerDataModel>()), Times.Once);
+    Assert.That(flag);
+}
+[Test]
+public void InsertWorker_RecordWithExistsData_ThrowException_Test()
+{
+    //Arrange 
+    _workerStorageContract.Setup(x =>
+    x.AddElement(It.IsAny<WorkerDataModel>())).Throws(new
+    ElementExistsException("Data", "Data"));
+    //Act&Assert
+    Assert.That(() =>
+    _workerBusinessLogicContract.InsertWorker(new(Guid.NewGuid().ToString(), "fio",
+    Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+    false)), Throws.TypeOf<ElementExistsException>());
+    _workerStorageContract.Verify(x =>
+    x.AddElement(It.IsAny<WorkerDataModel>()), Times.Once);
+}
+[Test]
+public void InsertWorker_NullRecord_ThrowException_Test()
+{
+    //Act&Assert
+    Assert.That(() => _workerBusinessLogicContract.InsertWorker(null),
+    Throws.TypeOf<ArgumentNullException>());
+    _workerStorageContract.Verify(x =>
+    x.AddElement(It.IsAny<WorkerDataModel>()), Times.Never);
+}
+[Test]
+public void InsertWorker_InvalidRecord_ThrowException_Test()
+{
+    //Act&Assert
+    Assert.That(() => _workerBusinessLogicContract.InsertWorker(new
+    WorkerDataModel("id", "fio", Guid.NewGuid().ToString(), DateTime.Now.AddYears(-
+    16).AddDays(-1), DateTime.Now, false)), Throws.TypeOf<ValidationException>());
+    _workerStorageContract.Verify(x =>
+    x.AddElement(It.IsAny<WorkerDataModel>()), Times.Never);
+}
+[Test]
+public void InsertWorker_StorageThrowError_ThrowException_Test()
+{
+    //Arrange
+    _workerStorageContract.Setup(x =>
+    x.AddElement(It.IsAny<WorkerDataModel>())).Throws(new StorageException(new
+    InvalidOperationException()));
+    //Act&Assert
+    Assert.That(() =>
+    _workerBusinessLogicContract.InsertWorker(new(Guid.NewGuid().ToString(), "fio",
+    Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+    false)), Throws.TypeOf<StorageException>());
+    _workerStorageContract.Verify(x =>
+    x.AddElement(It.IsAny<WorkerDataModel>()), Times.Once);
+}
+[Test]
+public void UpdateWorker_CorrectRecord_Test()
+{
+    //Arrange
+    var flag = false;
+    var record = new WorkerDataModel(Guid.NewGuid().ToString(), "fio",
+    Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+    false);
+    _workerStorageContract.Setup(x =>
+    x.UpdElement(It.IsAny<WorkerDataModel>()))
+    .Callback((WorkerDataModel x) =>
+    {
+        flag = x.Id == record.Id && x.FIO == record.FIO &&
+        x.PostId == record.PostId && x.BirthDate == record.BirthDate && 
+        x.EmploymentDate == record.EmploymentDate &&
+        x.IsDeleted == record.IsDeleted;
+    });
+    //Act
+    _workerBusinessLogicContract.UpdateWorker(record);
+    //Assert
+    _workerStorageContract.Verify(x =>
+    x.UpdElement(It.IsAny<WorkerDataModel>()), Times.Once);
+    Assert.That(flag);
+}
+[Test]
+public void UpdateWorker_RecordWithIncorrectData_ThrowException_Test()
+{
+    //Arrange
+    _workerStorageContract.Setup(x =>
+    x.UpdElement(It.IsAny<WorkerDataModel>())).Throws(new
+    ElementNotFoundException(""));
+    //Act&Assert
+    Assert.That(() =>
+    _workerBusinessLogicContract.UpdateWorker(new(Guid.NewGuid().ToString(), "fio",
+    Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+    false)), Throws.TypeOf<ElementNotFoundException>());
+    _workerStorageContract.Verify(x =>
+    x.UpdElement(It.IsAny<WorkerDataModel>()), Times.Once);
+}
+[Test]
+public void UpdateWorker_NullRecord_ThrowException_Test()
+{
+    //Act&Assert
+    Assert.That(() => _workerBusinessLogicContract.UpdateWorker(null),
+    Throws.TypeOf<ArgumentNullException>());
+    _workerStorageContract.Verify(x =>
+    x.UpdElement(It.IsAny<WorkerDataModel>()), Times.Never);
+}
+[Test]
+public void UpdateWorker_InvalidRecord_ThrowException_Test()
+{
+    //Act&Assert
+    Assert.That(() => _workerBusinessLogicContract.UpdateWorker(new
+    WorkerDataModel("id", "fio", Guid.NewGuid().ToString(), DateTime.Now.AddYears(-
+    16).AddDays(-1), DateTime.Now, false)), Throws.TypeOf<ValidationException>());
+    _workerStorageContract.Verify(x =>
+    x.UpdElement(It.IsAny<WorkerDataModel>()), Times.Never);
+}
+[Test]
+public void UpdateWorker_StorageThrowError_ThrowException_Test()
+{
+    //Arrange
+    _workerStorageContract.Setup(x =>
+    x.UpdElement(It.IsAny<WorkerDataModel>())).Throws(new StorageException(new
+    InvalidOperationException()));
+    //Act&Assert
+    Assert.That(() =>
+    _workerBusinessLogicContract.UpdateWorker(new(Guid.NewGuid().ToString(), "fio",
+    Guid.NewGuid().ToString(), DateTime.Now.AddYears(-16).AddDays(-1), DateTime.Now,
+    false)), Throws.TypeOf<StorageException>());
+    _workerStorageContract.Verify(x =>
+    x.UpdElement(It.IsAny<WorkerDataModel>()), Times.Once);
+} 
+[Test]
+public void DeleteWorker_CorrectRecord_Test()
+{
+    //Arrange
+    var id = Guid.NewGuid().ToString();
+    var flag = false;
+    _workerStorageContract.Setup(x => x.DelElement(It.Is((string x) => x
+    == id))).Callback(() => { flag = true; });
+    //Act
+    _workerBusinessLogicContract.DeleteWorker(id);
+    //Assert
+    _workerStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+    Times.Once);
+    Assert.That(flag);
+}
+[Test]
+public void DeleteWorker_RecordWithIncorrectId_ThrowException_Test()
+{
+    //Arrange
+    var id = Guid.NewGuid().ToString();
+    _workerStorageContract.Setup(x => x.DelElement(It.Is((string x) => x
+    != id))).Throws(new ElementNotFoundException(id));
+    //Act&Assert
+    Assert.That(() =>
+    _workerBusinessLogicContract.DeleteWorker(Guid.NewGuid().ToString()),
+    Throws.TypeOf<ElementNotFoundException>());
+    _workerStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+    Times.Once);
+}
+[Test]
+public void DeleteWorker_IdIsNullOrEmpty_ThrowException_Test()
+{
+    //Act&Assert
+    Assert.That(() => _workerBusinessLogicContract.DeleteWorker(null),
+    Throws.TypeOf<ArgumentNullException>());
+    Assert.That(() =>
+    _workerBusinessLogicContract.DeleteWorker(string.Empty),
+    Throws.TypeOf<ArgumentNullException>());
+    _workerStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+    Times.Never);
+}
+[Test]
+public void DeleteWorker_IdIsNotGuid_ThrowException_Test()
+{
+    //Act&Assert
+    Assert.That(() => _workerBusinessLogicContract.DeleteWorker("id"),
+    Throws.TypeOf<ValidationException>());
+    _workerStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+    Times.Never);
+}
+[Test]
+public void DeleteWorker_StorageThrowError_ThrowException_Test()
+{
+    //Arrange
+    _workerStorageContract.Setup(x =>
+    x.DelElement(It.IsAny<string>())).Throws(new StorageException(new
+    InvalidOperationException()));
+    //Act&Assert 
+    Assert.That(() =>
+    _workerBusinessLogicContract.DeleteWorker(Guid.NewGuid().ToString()),
+    Throws.TypeOf<StorageException>());
+    _workerStorageContract.Verify(x => x.DelElement(It.IsAny<string>()),
+    Times.Once);
+}
+}
+
--- a/SmallSoftwareProject/SmallSoftwareTests/DataModelsTests/PostDataModelTests.cs
+++ b/SmallSoftwareProject/SmallSoftwareTests/DataModelsTests/PostDataModelTests.cs
@@ -15,40 +15,18 @@ internal class PostDataModelTests
    [Test]
    public void IdIsNullOrEmptyTest()
    {
-        var post = CreateDataModel(null, Guid.NewGuid().ToString(), "name",
+        var post = CreateDataModel(null, "name",
        PostType.SoftInstaller, 10, true, DateTime.UtcNow);
        Assert.That(() => post.Validate(),
        Throws.TypeOf<ValidationException>());
-        post = CreateDataModel(string.Empty, Guid.NewGuid().ToString(),
-        "name", PostType.SoftInstaller, 10, true, DateTime.UtcNow);
+        post = CreateDataModel(string.Empty, "name", PostType.SoftInstaller, 10, true, DateTime.UtcNow);
        Assert.That(() => post.Validate(),
        Throws.TypeOf<ValidationException>());
    }
    [Test]
    public void IdIsNotGuidTest()
    {
-        var post = CreateDataModel("id", Guid.NewGuid().ToString(), "name",
-        PostType.SoftInstaller, 10, true, DateTime.UtcNow);
-        Assert.That(() => post.Validate(),
-        Throws.TypeOf<ValidationException>());
-    }
-    [Test]
-    public void PostIdIsNullEmptyTest()
-    {
-        var post = CreateDataModel(Guid.NewGuid().ToString(), null, "name",
-        PostType.SoftInstaller, 10, true, DateTime.UtcNow);
-        Assert.That(() => post.Validate(),
-        Throws.TypeOf<ValidationException>());
-        post = CreateDataModel(Guid.NewGuid().ToString(), string.Empty,
-        "name", PostType.SoftInstaller, 10, true, DateTime.UtcNow);
-        Assert.That(() => post.Validate(),
-        Throws.TypeOf<ValidationException>());
-    }
-    [Test]
-    public void PostIdIsNotGuidTest()
-    {
-        var post = CreateDataModel(Guid.NewGuid().ToString(), "postId",
-        "name", PostType.SoftInstaller, 10, true, DateTime.UtcNow);
+        var post = CreateDataModel("id", "name", PostType.SoftInstaller, 10, true, DateTime.UtcNow);
        Assert.That(() => post.Validate(),
        Throws.TypeOf<ValidationException>());
    }
@@ -56,12 +34,10 @@ internal class PostDataModelTests

    public void PostNameIsEmptyTest()
    {
-        var manufacturer = CreateDataModel(Guid.NewGuid().ToString(),
-        Guid.NewGuid().ToString(), null, PostType.SoftInstaller, 10, true, DateTime.UtcNow);
+        var manufacturer = CreateDataModel(Guid.NewGuid().ToString(), null, PostType.SoftInstaller, 10, true, DateTime.UtcNow);
        Assert.That(() => manufacturer.Validate(),
        Throws.TypeOf<ValidationException>());
-        manufacturer = CreateDataModel(Guid.NewGuid().ToString(),
-        Guid.NewGuid().ToString(), string.Empty, PostType.SoftInstaller, 10, true,
+        manufacturer = CreateDataModel(Guid.NewGuid().ToString(), string.Empty, PostType.SoftInstaller, 10, true,
        DateTime.UtcNow);
        Assert.That(() => manufacturer.Validate(),
        Throws.TypeOf<ValidationException>());
@@ -69,8 +45,7 @@ internal class PostDataModelTests
    [Test]
    public void PostTypeIsNoneTest()
    {
-        var post = CreateDataModel(Guid.NewGuid().ToString(),
-        Guid.NewGuid().ToString(), "name", PostType.None, 10, true, DateTime.UtcNow);
+        var post = CreateDataModel(Guid.NewGuid().ToString(), "name", PostType.None, 10, true, DateTime.UtcNow);
        Assert.That(() => post.Validate(),
        Throws.TypeOf<ValidationException>());
    }
@@ -78,11 +53,10 @@ internal class PostDataModelTests
    public void SalaryIsLessOrZeroTest()
    {
        var post = CreateDataModel(Guid.NewGuid().ToString(),
-        Guid.NewGuid().ToString(), "name", PostType.SoftInstaller, 0, true, DateTime.UtcNow);
+        "name", PostType.SoftInstaller, 0, true, DateTime.UtcNow);
        Assert.That(() => post.Validate(),
        Throws.TypeOf<ValidationException>());
-        post = CreateDataModel(Guid.NewGuid().ToString(),
-        Guid.NewGuid().ToString(), "name", PostType.SoftInstaller, -10, true,
+        post = CreateDataModel(Guid.NewGuid().ToString(), "name", PostType.SoftInstaller, -10, true,
        DateTime.UtcNow);
        Assert.That(() => post.Validate(),
        Throws.TypeOf<ValidationException>());
@@ -97,13 +71,12 @@ internal class PostDataModelTests
        var salary = 10;
        var isActual = false;
        var changeDate = DateTime.UtcNow.AddDays(-1);
-        var post = CreateDataModel(postId, postPostId, postName, postType,
+        var post = CreateDataModel(postId, postName, postType,
        salary, isActual, changeDate);
        Assert.That(() => post.Validate(), Throws.Nothing);
        Assert.Multiple(() =>
        {
            Assert.That(post.Id, Is.EqualTo(postId));
-            Assert.That(post.PostId, Is.EqualTo(postPostId));
            Assert.That(post.PostName, Is.EqualTo(postName));
            Assert.That(post.PostType, Is.EqualTo(postType));
            Assert.That(post.Salary, Is.EqualTo(salary));
@@ -111,8 +84,8 @@ internal class PostDataModelTests
            Assert.That(post.ChangeDate, Is.EqualTo(changeDate));
        });
    }
-    private static PostDataModel CreateDataModel(string? id, string? postId,
+    private static PostDataModel CreateDataModel(string? id, 
    string? postName, PostType postType, double salary, bool isActual, DateTime
    changeDate) => 
-        new (id, postId, postName, postType, salary, isActual, changeDate);
+        new (id, postName, postType, salary, isActual, changeDate);
 }
--- a/SmallSoftwareProject/SmallSoftwareTests/SmallSoftwareTests.csproj
+++ b/SmallSoftwareProject/SmallSoftwareTests/SmallSoftwareTests.csproj
@@ -11,12 +11,14 @@
  <ItemGroup>
    <PackageReference Include="coverlet.collector" Version="6.0.2" />
    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
+    <PackageReference Include="Moq" Version="4.20.72" />
    <PackageReference Include="NUnit" Version="4.2.2" />
    <PackageReference Include="NUnit.Analyzers" Version="4.4.0" />
    <PackageReference Include="NUnit3TestAdapter" Version="4.6.0" />
  </ItemGroup>

  <ItemGroup>
+    <ProjectReference Include="..\SmallSoftwareBusinessLogic\SmallSoftwareBusinessLogic.csproj" />
    <ProjectReference Include="..\SmallSoftwareContracts\SmallSoftwareContracts.csproj" />
  </ItemGroup>