Наследование ISaleStorage

This reverts commit 9045e90326.

SquirrelContract/SquirrelContract.sln

@@ -9,6 +9,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SquirrelTests", "SquirrelTe
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SquirrelBusinessLogic", "SquirrelBusinessLogic\SquirrelBusinessLogic.csproj", "{C03D0604-CD06-42DA-99CB-23B8306C3714}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SquirrelDatabase", "SquirrelDatabase\SquirrelDatabase.csproj", "{A8A7A434-A278-4362-8D34-C2E3CAA938C1}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -27,6 +29,10 @@ Global
 		{C03D0604-CD06-42DA-99CB-23B8306C3714}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{C03D0604-CD06-42DA-99CB-23B8306C3714}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{C03D0604-CD06-42DA-99CB-23B8306C3714}.Release|Any CPU.Build.0 = Release|Any CPU
+		{A8A7A434-A278-4362-8D34-C2E3CAA938C1}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{A8A7A434-A278-4362-8D34-C2E3CAA938C1}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{A8A7A434-A278-4362-8D34-C2E3CAA938C1}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{A8A7A434-A278-4362-8D34-C2E3CAA938C1}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

SquirrelContract/SquirrelContract/DataModels/PostDataModel.cs

@@ -5,9 +5,9 @@ using SquirrelContract.Infastructure;
 
 namespace SquirrelContract.DataModels;
 
-public class PostDataModel(string id, string postName, PostType postType, double salary, bool isActual, DateTime changeDate) : IValidation
+public class PostDataModel(string postId, string postName, PostType postType, double salary, bool isActual, DateTime changeDate) : IValidation
 {
-    public string Id { get; private set; } = id;
+    public string Id { get; private set; } = postId;
 
     public string PostName { get; private set; } = postName;
 

SquirrelContract/SquirrelContract/DataModels/SaleDataModel.cs

@@ -5,7 +5,7 @@ using SquirrelContract.Infastructure;
 
 namespace SquirrelContract.DataModels;
 
-public class SaleDataModel(string id, string employeeId, string? clientId, double sum, DiscountType discountType, double discount, bool isCancel, List<SaleCocktailDataModel> cocktails) : IValidation
+public class SaleDataModel(string id, string employeeId, string? clientId, double sum, DiscountType discountType, double discount, bool isCancel, List<SaleCocktailDataModel> saleCocktails) : IValidation
 {
     public string Id { get; private set; } = id;
 
@@ -20,10 +20,10 @@ public class SaleDataModel(string id, string employeeId, string? clientId, doubl
     public DiscountType DiscountType { get; private set; } = discountType;
 
     public double Discount { get; private set; } = discount;
-
+    
     public bool IsCancel { get; private set; } = isCancel;
 
-    public List<SaleCocktailDataModel> Cocktails { get; private set; } = cocktails;
+    public List<SaleCocktailDataModel> Cocktails { get; private set; } = saleCocktails;
 
     public void Validate()
     {

SquirrelContract/SquirrelContract/Exceptions/ElementDeletedException.cs

@@ -0,0 +1,6 @@
+namespace SquirrelContract.Exceptions;
+
+public class ElementDeletedException : Exception
+{
+	public ElementDeletedException(string id) : base($"Cannot modify a deleted item (id: {id})") { }
+}

SquirrelContract/SquirrelContract/Infastructure/IConfigurationDatabase.cs

@@ -0,0 +1,6 @@
+namespace SquirrelContract.Infastructure;
+
+public interface IConfigurationDatabase
+{
+    string ConnectionString { get; }
+}

SquirrelContract/SquirrelDatabase/Implementations/ClientStorageContract.cs

@@ -0,0 +1,149 @@
+using AutoMapper;
+using Microsoft.EntityFrameworkCore;
+using Npgsql;
+using SquirrelContract.DataModels;
+using SquirrelContract.Exceptions;
+using SquirrelContract.StoragesContracts;
+using SquirrelDatabase.Models;
+using System;
+
+namespace SquirrelDatabase.Implementations;
+
+public class ClientStorageContract : IClientStorageContract
+{
+    private readonly SquirrelDbContext _dbContext;
+    private readonly Mapper _mapper;
+
+    public ClientStorageContract(SquirrelDbContext squirrelDbContext)
+    {
+        _dbContext = squirrelDbContext;
+        var config = new MapperConfiguration(cfg =>
+        {
+            cfg.AddMaps(typeof(SquirrelDbContext).Assembly);
+        });
+        _mapper = new Mapper(config);
+    }
+
+    public List<ClientDataModel> GetList()
+    {
+        try
+        {
+            return [.. _dbContext.Clients.Select(x => _mapper.Map<ClientDataModel>(x))];
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public ClientDataModel? GetElementById(string id)
+    {
+        try
+        {
+            return _mapper.Map<ClientDataModel>(GetClientById(id));
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public ClientDataModel? GetElementByFIO(string fio)
+    {
+        try
+        {
+            return _mapper.Map<ClientDataModel>(_dbContext.Clients.FirstOrDefault(x => x.FIO == fio));
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public ClientDataModel? GetElementByPhoneNumber(string phoneNumber)
+    {
+        try
+        {
+            return _mapper.Map<ClientDataModel>(_dbContext.Clients.FirstOrDefault(x => x.PhoneNumber == phoneNumber));
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void AddElement(ClientDataModel clientDataModel)
+    {
+        try
+        {
+            _dbContext.Clients.Add(_mapper.Map<Client>(clientDataModel));
+            _dbContext.SaveChanges();
+        }
+        catch (InvalidOperationException ex) when (ex.TargetSite?.Name == "ThrowIdentityConflict")
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new ElementExistsException("Id", clientDataModel.Id);
+        }
+        catch (DbUpdateException ex) when (ex.InnerException is PostgresException { ConstraintName: "IX_Clients_PhoneNumber" })
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new ElementExistsException("PhoneNumber", clientDataModel.PhoneNumber);
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void UpdElement(ClientDataModel clientDataModel)
+    {
+        try
+        {
+            var element = GetClientById(clientDataModel.Id) ?? throw new ElementNotFoundException(clientDataModel.Id);
+            _dbContext.Clients.Update(_mapper.Map(clientDataModel, element));
+            _dbContext.SaveChanges();
+        }
+        catch (ElementNotFoundException)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw;
+        }
+        catch (DbUpdateException ex) when (ex.InnerException is PostgresException { ConstraintName: "IX_Clients_PhoneNumber" })
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new ElementExistsException("PhoneNumber", clientDataModel.PhoneNumber);
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void DelElement(string id)
+    {
+        try
+        {
+            var element = GetClientById(id) ?? throw new ElementNotFoundException(id);
+            _dbContext.Clients.Remove(element);
+            _dbContext.SaveChanges();
+        }
+        catch (ElementNotFoundException)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw;
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    private Client? GetClientById(string id) => _dbContext.Clients.FirstOrDefault(x => x.Id == id);
+}

SquirrelContract/SquirrelDatabase/Implementations/CocktailStorageContract.cs

@@ -0,0 +1,164 @@
+using AutoMapper;
+using Microsoft.EntityFrameworkCore;
+using Npgsql;
+using SquirrelContract.DataModels;
+using SquirrelContract.Exceptions;
+using SquirrelContract.StoragesContracts;
+using SquirrelDatabase.Models;
+
+namespace SquirrelDatabase.Implementations;
+
+public class CocktailStorageContract : ICocktailStorageContract
+{
+    private readonly SquirrelDbContext _dbContext;
+    private readonly Mapper _mapper;
+
+    public CocktailStorageContract(SquirrelDbContext dbContext)
+    {
+        _dbContext = dbContext;
+        var config = new MapperConfiguration(cfg =>
+        {
+            cfg.CreateMap<Cocktail, CocktailDataModel>();
+            cfg.CreateMap<CocktailDataModel, Cocktail>();
+            cfg.CreateMap<CocktailHistory, CocktailHistoryDataModel>();
+        });
+        _mapper = new Mapper(config);
+    }
+
+    public List<CocktailDataModel> GetList()
+    {
+        try
+        {
+            return [.. _dbContext.Cocktails.Select(x => _mapper.Map<CocktailDataModel>(x))];
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public List<CocktailHistoryDataModel> GetHistoryByCocktailId(string cocktailId)
+    {
+        try
+        {
+            return [.. _dbContext.CocktailHistories.Where(x => x.CocktailId == cocktailId).OrderByDescending(x => x.ChangeDate).Select(x => _mapper.Map<CocktailHistoryDataModel>(x))];
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public CocktailDataModel? GetElementById(string id)
+    {
+        try
+        {
+            return _mapper.Map<CocktailDataModel>(GetCocktailById(id));
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public CocktailDataModel? GetElementByName(string name)
+    {
+        try
+        {
+            return _mapper.Map<CocktailDataModel>(_dbContext.Cocktails.FirstOrDefault(x => x.CocktailName == name));
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void AddElement(CocktailDataModel cocktailDataModel)
+    {
+        try
+        {
+            _dbContext.Cocktails.Add(_mapper.Map<Cocktail>(cocktailDataModel));
+            _dbContext.SaveChanges();
+        }
+        catch (InvalidOperationException ex) when (ex.TargetSite?.Name == "ThrowIdentityConflict")
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new ElementExistsException("Id", cocktailDataModel.Id);
+        }
+        catch (DbUpdateException ex) when (ex.InnerException is PostgresException { ConstraintName: "IX_Cocktails_CocktailName" })
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new ElementExistsException("CocktailName", cocktailDataModel.CocktailName);
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void UpdElement(CocktailDataModel cocktailDataModel)
+    {
+        try
+        {
+            var element = GetCocktailById(cocktailDataModel.Id) ?? throw new ElementNotFoundException(cocktailDataModel.Id);
+            _dbContext.Cocktails.Update(_mapper.Map(cocktailDataModel, element));
+            _dbContext.SaveChanges();
+        }
+        catch (ElementNotFoundException)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw;
+        }
+        catch (DbUpdateException ex) when (ex.InnerException is PostgresException { ConstraintName: "IX_Cocktails_CocktailName" })
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new ElementExistsException("CocktailName", cocktailDataModel.CocktailName);
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void DelElement(string id)
+    {
+        try
+        {
+            var element = GetCocktailById(id) ?? throw new ElementNotFoundException(id);
+            _dbContext.Cocktails.Remove(element);
+            _dbContext.SaveChanges();
+        }
+        catch (ElementNotFoundException)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw;
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void ResElement(string id)
+    {
+        try
+        {
+            var element = GetCocktailById(id) ?? throw new ElementNotFoundException(id);
+            _dbContext.SaveChanges();
+        }
+        catch
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw;
+        }
+    }
+
+    private Cocktail? GetCocktailById(string id) => _dbContext.Cocktails.FirstOrDefault(x => x.Id == id);
+}

SquirrelContract/SquirrelDatabase/Implementations/EmployeeStorageContract.cs

@@ -0,0 +1,153 @@
+using AutoMapper;
+using SquirrelContract.DataModels;
+using SquirrelContract.Exceptions;
+using SquirrelContract.StoragesContracts;
+using SquirrelDatabase.Models;
+
+namespace SquirrelDatabase.Implementations;
+
+public class EmployeeStorageContract : IEmployeeStorageContract
+{
+    private readonly SquirrelDbContext _dbContext;
+    private readonly Mapper _mapper;
+
+    public EmployeeStorageContract(SquirrelDbContext dbContext)
+    {
+        _dbContext = dbContext;
+        var config = new MapperConfiguration(cfg =>
+        {
+            cfg.AddMaps(typeof(SquirrelDbContext).Assembly);
+        });
+        _mapper = new Mapper(config);
+    }
+
+    public List<EmployeeDataModel> GetList(bool onlyActive = true, string? postId = null, DateTime? fromBirthDate = null, DateTime? toBirthDate = null, DateTime? fromEmploymentDate = null, DateTime? toEmploymentDate = null)
+    {
+        try
+        {
+            var query = _dbContext.Employees.AsQueryable();
+            if (onlyActive)
+            {
+                query = query.Where(x => !x.IsDeleted);
+            }
+            if (postId is not null)
+            {
+                query = query.Where(x => x.PostId == postId);
+            }
+            if (fromBirthDate is not null && toBirthDate is not null)
+            {
+                query = query.Where(x => x.BirthDate >= fromBirthDate && x.BirthDate <= toBirthDate);
+            }
+            if (fromEmploymentDate is not null && toEmploymentDate is not null)
+            {
+                query = query.Where(x => x.EmploymentDate >= fromEmploymentDate && x.EmploymentDate <= toEmploymentDate);
+            }
+            return [.. query.Select(x => _mapper.Map<EmployeeDataModel>(x))];
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public EmployeeDataModel? GetElementById(string id)
+    {
+        try
+        {
+            return _mapper.Map<EmployeeDataModel>(GetEmployeeById(id));
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public EmployeeDataModel? GetElementByFIO(string fio)
+    {
+        try
+        {
+            return _mapper.Map<EmployeeDataModel>(_dbContext.Employees.FirstOrDefault(x => x.FIO == fio));
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public EmployeeDataModel? GetElementByEmail(string email)
+    {
+        try
+        {
+            return _mapper.Map<EmployeeDataModel>(_dbContext.Employees.FirstOrDefault(x => x.Email == email));
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void AddElement(EmployeeDataModel employeeDataModel)
+    {
+        try
+        {
+            _dbContext.Employees.Add(_mapper.Map<Employee>(employeeDataModel));
+            _dbContext.SaveChanges();
+        }
+        catch (InvalidOperationException ex) when (ex.TargetSite?.Name == "ThrowIdentityConflict")
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new ElementExistsException("Id", employeeDataModel.Id);
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void UpdElement(EmployeeDataModel employeeDataModel)
+    {
+        try
+        {
+            var element = GetEmployeeById(employeeDataModel.Id) ?? throw new ElementNotFoundException(employeeDataModel.Id);
+            _dbContext.Employees.Update(_mapper.Map(employeeDataModel, element));
+            _dbContext.SaveChanges();
+        }
+        catch (ElementNotFoundException)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw;
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void DelElement(string id)
+    {
+        try
+        {
+            var element = GetEmployeeById(id) ?? throw new ElementNotFoundException(id);
+            element.IsDeleted = true;
+            _dbContext.SaveChanges();
+        }
+        catch (ElementNotFoundException)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw;
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    private Employee? GetEmployeeById(string id) => _dbContext.Employees.FirstOrDefault(x => x.Id == id && !x.IsDeleted);
+}

SquirrelContract/SquirrelDatabase/Implementations/PostStorageContract.cs

@@ -0,0 +1,190 @@
+using AutoMapper;
+using Microsoft.EntityFrameworkCore;
+using Npgsql;
+using SquirrelContract.DataModels;
+using SquirrelContract.Exceptions;
+using SquirrelContract.StoragesContracts;
+using SquirrelDatabase.Models;
+
+namespace SquirrelDatabase.Implementations;
+
+public class PostStorageContract : IPostStorageContract
+{
+    private readonly SquirrelDbContext _dbContext;
+    private readonly Mapper _mapper;
+
+    public PostStorageContract(SquirrelDbContext dbContext)
+    {
+        _dbContext = dbContext;
+        var config = new MapperConfiguration(cfg =>
+        {
+            cfg.CreateMap<Post, PostDataModel>()
+                .ForMember(x => x.Id, x => x.MapFrom(src => src.PostId));
+            cfg.CreateMap<PostDataModel, Post>()
+                .ForMember(x => x.Id, x => x.Ignore())
+                .ForMember(x => x.PostId, x => x.MapFrom(src => src.Id))
+                .ForMember(x => x.IsActual, x => x.MapFrom(src => true))
+                .ForMember(x => x.ChangeDate, x => x.MapFrom(src => DateTime.UtcNow));
+        });
+        _mapper = new Mapper(config);
+    }
+
+    public List<PostDataModel> GetList(bool onlyActual = true)
+    {
+        try
+        {
+            var query = _dbContext.Posts.AsQueryable();
+            if (onlyActual)
+            {
+                query = query.Where(x => x.IsActual);
+            }
+            return [.. query.Select(x => _mapper.Map<PostDataModel>(x))];
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public List<PostDataModel> GetPostWithHistory(string postId)
+    {
+        try
+        {
+            return [.. _dbContext.Posts.Where(x => x.PostId == postId).Select(x => _mapper.Map<PostDataModel>(x))];
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public PostDataModel? GetElementById(string id)
+    {
+        try
+        {
+            return _mapper.Map<PostDataModel>(_dbContext.Posts.FirstOrDefault(x => x.PostId == id && x.IsActual));
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public PostDataModel? GetElementByName(string name)
+    {
+        try
+        {
+            return _mapper.Map<PostDataModel>(_dbContext.Posts.FirstOrDefault(x => x.PostName == name && x.IsActual));
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void AddElement(PostDataModel postDataModel)
+    {
+        try
+        {
+            _dbContext.Posts.Add(_mapper.Map<Post>(postDataModel));
+            _dbContext.SaveChanges();
+        }
+        catch (DbUpdateException ex) when (ex.InnerException is PostgresException { ConstraintName: "IX_Posts_PostName_IsActual" })
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new ElementExistsException("PostName", postDataModel.PostName);
+        }
+        catch (DbUpdateException ex) when (ex.InnerException is PostgresException { ConstraintName: "IX_Posts_PostId_IsActual" })
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new ElementExistsException("PostId", postDataModel.Id);
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void UpdElement(PostDataModel postDataModel)
+    {
+        try
+        {
+            var transaction = _dbContext.Database.BeginTransaction();
+            try
+            {
+                var element = GetPostById(postDataModel.Id) ?? throw new ElementNotFoundException(postDataModel.Id);
+                if (!element.IsActual)
+                {
+                    throw new ElementDeletedException(postDataModel.Id);
+                }
+                element.IsActual = false;
+                _dbContext.SaveChanges();
+                var newElement = _mapper.Map<Post>(postDataModel);
+                _dbContext.Posts.Add(newElement);
+                _dbContext.SaveChanges();
+                transaction.Commit();
+            }
+            catch
+            {
+                transaction.Rollback();
+                throw;
+            }
+        }
+        catch (DbUpdateException ex) when (ex.InnerException is PostgresException { ConstraintName: "IX_Posts_PostName_IsActual" })
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new ElementExistsException("PostName", postDataModel.PostName);
+        }
+        catch (Exception ex) when (ex is ElementDeletedException || ex is ElementNotFoundException)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw;
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void DelElement(string id)
+    {
+        try
+        {
+            var element = GetPostById(id) ?? throw new ElementNotFoundException(id);
+            if (!element.IsActual)
+            {
+                throw new ElementDeletedException(id);
+            }
+            element.IsActual = false;
+            _dbContext.SaveChanges();
+        }
+        catch
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw;
+        }
+    }
+
+    public void ResElement(string id)
+    {
+        try
+        {
+            var element = GetPostById(id) ?? throw new ElementNotFoundException(id);
+            element.IsActual = true;
+            _dbContext.SaveChanges();
+        }
+        catch
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw;
+        }
+    }
+
+    private Post? GetPostById(string id) => _dbContext.Posts.Where(x => x.PostId == id).OrderByDescending(x => x.ChangeDate).FirstOrDefault();
+}

SquirrelContract/SquirrelDatabase/Implementations/SalaryStorageContract.cs

@@ -0,0 +1,57 @@
+using AutoMapper;
+using BarBelochkaContract.DataModels;
+using SquirrelContract.Exceptions;
+using SquirrelContract.StoragesContracts;
+using SquirrelDatabase.Models;
+
+namespace SquirrelDatabase.Implementations;
+
+public class SalaryStorageContract : ISalaryStorageContract
+{
+    private readonly SquirrelDbContext _dbContext;
+    private readonly Mapper _mapper;
+
+    public SalaryStorageContract(SquirrelDbContext dbContext)
+    {
+        _dbContext = dbContext;
+        var config = new MapperConfiguration(cfg =>
+        {
+            cfg.CreateMap<Salary, SalaryDataModel>();
+            cfg.CreateMap<SalaryDataModel, Salary>()
+                .ForMember(dest => dest.EmployeeSalary, opt => opt.MapFrom(src => src.Salary));
+        });
+        _mapper = new Mapper(config);
+    }
+
+    public List<SalaryDataModel> GetList(DateTime startDate, DateTime endDate, string? employeeId = null)
+    {
+        try
+        {
+            var query = _dbContext.Salaries.Where(x => x.SalaryDate >= startDate && x.SalaryDate <= endDate);
+            if (employeeId is not null)
+            {
+                query = query.Where(x => x.EmployeeId == employeeId);
+            }
+            return [.. query.Select(x => _mapper.Map<SalaryDataModel>(x))];
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void AddElement(SalaryDataModel salaryDataModel)
+    {
+        try
+        {
+            _dbContext.Salaries.Add(_mapper.Map<Salary>(salaryDataModel));
+            _dbContext.SaveChanges();
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+}

SquirrelContract/SquirrelDatabase/Implementations/SaleStorageContract.cs

@@ -0,0 +1,112 @@
+using AutoMapper;
+using Microsoft.EntityFrameworkCore;
+using SquirrelContract.DataModels;
+using SquirrelContract.Exceptions;
+using SquirrelContract.StoragesContracts;
+using SquirrelDatabase.Models;
+
+namespace SquirrelDatabase.Implementations;
+
+public class SaleStorageContract : ISaleStorageContract
+{
+    private readonly SquirrelDbContext _dbContext;
+    private readonly Mapper _mapper;
+
+    public SaleStorageContract(SquirrelDbContext dbContext)
+    {
+        _dbContext = dbContext;
+        var config = new MapperConfiguration(cfg =>
+        {
+            cfg.CreateMap<SaleCocktail, SaleCocktailDataModel>();
+            cfg.CreateMap<SaleCocktailDataModel, SaleCocktail>();
+            cfg.CreateMap<Sale, SaleDataModel>();
+            cfg.CreateMap<SaleDataModel, Sale>()
+                .ForMember(x => x.IsCancel, x => x.MapFrom(src => false))
+                .ForMember(x => x.SaleCocktails, x => x.MapFrom(src => src.Cocktails));
+        });
+        _mapper = new Mapper(config);
+    }
+
+    public List<SaleDataModel> GetList(DateTime? startDate = null, DateTime? endDate = null, string? employeeId = null, string? clientId = null, string? cocktailId = null)
+    {
+        try
+        {
+            var query = _dbContext.Sales.Include(x => x.SaleCocktails).AsQueryable();
+            if (startDate is not null && endDate is not null)
+            {
+                query = query.Where(x => x.SaleDate >= startDate && x.SaleDate < endDate);
+            }
+            if (employeeId is not null)
+            {
+                query = query.Where(x => x.EmployeeId == employeeId);
+            }
+            if (clientId is not null)
+            {
+                query = query.Where(x => x.ClientId == clientId);
+            }
+            if (cocktailId is not null)
+            {
+                query = query.Where(x => x.SaleCocktails!.Any(y => y.CocktailId == cocktailId));
+            }
+            return [.. query.Select(x => _mapper.Map<SaleDataModel>(x))];
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public SaleDataModel? GetElementById(string id)
+    {
+        try
+        {
+            return _mapper.Map<SaleDataModel>(GetSaleById(id));
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void AddElement(SaleDataModel saleDataModel)
+    {
+        try
+        {
+            _dbContext.Sales.Add(_mapper.Map<Sale>(saleDataModel));
+            _dbContext.SaveChanges();
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    public void DelElement(string id)
+    {
+        try
+        {
+            var element = GetSaleById(id) ?? throw new ElementNotFoundException(id);
+            if (element.IsCancel)
+            {
+                throw new ElementDeletedException(id);
+            }
+            element.IsCancel = true;
+            _dbContext.SaveChanges();
+        }
+        catch (Exception ex) when (ex is ElementDeletedException || ex is ElementNotFoundException)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw;
+        }
+        catch (Exception ex)
+        {
+            _dbContext.ChangeTracker.Clear();
+            throw new StorageException(ex);
+        }
+    }
+
+    private Sale? GetSaleById(string id) => _dbContext.Sales.FirstOrDefault(x => x.Id == id);
+}

SquirrelContract/SquirrelDatabase/Models/Client.cs

@@ -0,0 +1,18 @@
+using AutoMapper;
+using SquirrelContract.DataModels;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace SquirrelDatabase.Models;
+
+[AutoMap(typeof(ClientDataModel), ReverseMap = true)]
+public class Client
+{
+    public required string Id { get; set; } = Guid.NewGuid().ToString();
+    public required string FIO { get; set; } 
+    public required string PhoneNumber { get; set; } 
+    public double DiscountSize { get; set; }
+
+    [ForeignKey("ClientId")]
+    public List<Sale>? Sales { get; set; }
+
+}

SquirrelContract/SquirrelDatabase/Models/Cocktail.cs

@@ -0,0 +1,18 @@
+using SquirrelContract.Enums;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace SquirrelDatabase.Models;
+
+public class Cocktail
+{
+    public required string Id { get; set; }
+    public required string CocktailName { get; set; }
+    public double Price { get; set; }
+    public required AlcoholType BaseAlcohol { get; set; }
+
+    [ForeignKey("CocktailId")]
+    public List<CocktailHistory>? CocktailHistories { get; set; }
+
+    [ForeignKey("CocktailId")]
+    public List<SaleCocktail>? SaleCocktails { get; set; }
+}

SquirrelContract/SquirrelDatabase/Models/CocktailHistory.cs

@@ -0,0 +1,14 @@
+namespace SquirrelDatabase.Models;
+
+public class CocktailHistory
+{
+    public string Id { get; set; } = Guid.NewGuid().ToString();
+
+    public required string CocktailId { get; set; }
+
+    public double OldPrice { get; set; }
+
+    public DateTime ChangeDate { get; set; }
+
+    public Cocktail? Cocktail { get; set; }
+}

SquirrelContract/SquirrelDatabase/Models/Employee.cs

@@ -0,0 +1,29 @@
+using AutoMapper;
+using SquirrelContract.DataModels;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace SquirrelDatabase.Models;
+
+[AutoMap(typeof(EmployeeDataModel), ReverseMap = true)]
+public class Employee
+{
+    public required string Id { get; set; }
+
+    public required string FIO { get; set; }
+
+    public string Email { get; set; }
+
+    public string PostId { get; set; }
+
+    public DateTime BirthDate { get; set; }
+
+    public DateTime EmploymentDate { get; set; }
+
+    public bool IsDeleted { get; set; }
+
+    [ForeignKey("EmployeeId")]
+    public List<Salary>? Salaries { get; set; }
+
+    [ForeignKey("EmployeeId")]
+    public List<Sale>? Sales { get; set; }
+}

SquirrelContract/SquirrelDatabase/Models/Post.cs

@@ -0,0 +1,22 @@
+using AutoMapper;
+using SquirrelContract.DataModels;
+using SquirrelContract.Enums;
+
+namespace SquirrelDatabase.Models;
+
+public class Post
+{
+    public required string Id { get; set; } = Guid.NewGuid().ToString();
+
+    public required string PostId { get; set; }
+
+    public required string PostName { get; set; }
+
+    public PostType PostType { get; set; }
+
+    public double Salary { get; set; }
+
+    public bool IsActual { get; set; }
+
+    public DateTime ChangeDate { get; set; }
+}

SquirrelContract/SquirrelDatabase/Models/Salary.cs

@@ -0,0 +1,18 @@
+using AutoMapper;
+using BarBelochkaContract.DataModels;
+
+namespace SquirrelDatabase.Models;
+
+public class Salary
+{
+    public string Id { get; set; } = Guid.NewGuid().ToString();
+
+    public required string EmployeeId { get; set; }
+
+    public DateTime SalaryDate { get; set; }
+
+    public double EmployeeSalary { get; set; }
+
+    public Employee? Employee { get; set; }
+
+}

SquirrelContract/SquirrelDatabase/Models/Sale.cs

@@ -0,0 +1,33 @@
+using AutoMapper;
+using BarBelochkaContract.DataModels;
+using SquirrelContract.DataModels;
+using SquirrelContract.Enums;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace SquirrelDatabase.Models;
+
+public class Sale
+{
+    public string Id { get; set; } = Guid.NewGuid().ToString();
+
+    public required string EmployeeId { get; set; }
+
+    public string? ClientId { get; set; }
+
+    public DateTime SaleDate { get; set; }
+
+    public double Sum { get; set; }
+
+    public DiscountType DiscountType { get; set; }
+
+    public double Discount { get; set; }
+
+    public bool IsCancel { get; set; }
+
+    public Employee? Employee { get; set; }  
+
+    public Client? Client { get; set; }
+
+    [ForeignKey("SaleId")]
+    public List<SaleCocktail>? SaleCocktails { get; set; }
+}

SquirrelContract/SquirrelDatabase/Models/SaleCocktail.cs

@@ -0,0 +1,10 @@
+namespace SquirrelDatabase.Models;
+
+public class SaleCocktail
+{
+    public required string SaleId { get; set; }
+
+    public required string CocktailId { get; set; }
+
+    public int Count { get; set; }
+}

SquirrelContract/SquirrelDatabase/SquirrelDatabase.csproj

@@ -0,0 +1,20 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="AutoMapper" Version="14.0.0" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.2" />
+    <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="9.0.3" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\SquirrelContract\SquirrelContract.csproj" />
+  </ItemGroup>
+
+</Project>

SquirrelContract/SquirrelDatabase/SquirrelDbContext.cs

@@ -0,0 +1,53 @@
+using Microsoft.EntityFrameworkCore;
+using SquirrelContract.Infastructure;
+using SquirrelDatabase.Models;
+
+namespace SquirrelDatabase;
+
+public class SquirrelDbContext(IConfigurationDatabase configurationDatabase) : DbContext
+{
+    private readonly IConfigurationDatabase? _configurationDatabase = configurationDatabase;
+
+    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+    {
+        optionsBuilder.UseNpgsql(_configurationDatabase?.ConnectionString, o => o.SetPostgresVersion(12, 2));
+        base.OnConfiguring(optionsBuilder);
+    }
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        base.OnModelCreating(modelBuilder);
+
+        modelBuilder.Entity<Client>().HasIndex(x => x.PhoneNumber).IsUnique();
+
+        modelBuilder.Entity<Cocktail>().HasIndex(x => x.CocktailName).IsUnique();
+
+        modelBuilder.Entity<Post>()
+            .HasIndex(e => new { e.PostName, e.IsActual })
+            .IsUnique()
+            .HasFilter($"\"{nameof(Post.IsActual)}\" = TRUE");
+
+        modelBuilder.Entity<Post>()
+            .HasIndex(e => new { e.PostId, e.IsActual })
+            .IsUnique()
+            .HasFilter($"\"{nameof(Post.IsActual)}\" = TRUE");
+
+        modelBuilder.Entity<SaleCocktail>().HasKey(x => new { x.SaleId, x.CocktailId });
+    }
+
+    public DbSet<Client> Clients { get; set; }
+
+    public DbSet<Post> Posts { get; set; }
+
+    public DbSet<Cocktail> Cocktails { get; set; }
+
+    public DbSet<CocktailHistory> CocktailHistories { get; set; }
+
+    public DbSet<Salary> Salaries { get; set; }
+
+    public DbSet<Sale> Sales { get; set; }
+
+    public DbSet<SaleCocktail> SaleCocktails { get; set; }
+
+    public DbSet<Employee> Employees { get; set; }
+}

SquirrelContract/SquirrelTests/Infrastructure/ConfigurationDatabaseTest.cs

@@ -0,0 +1,10 @@
+using SquirrelContract.Infastructure;
+
+namespace SquirrelTests.Infrastructure;
+
+internal class ConfigurationDatabaseTest : IConfigurationDatabase
+{
+    public string ConnectionString =>
+    "Host=127.0.0.1;Port=5432;Database=SquirrelTest;Username=postgres;Password=postgres;";
+}
+

SquirrelContract/SquirrelTests/SquirrelTests.csproj

@@ -20,6 +20,7 @@
   <ItemGroup>
     <ProjectReference Include="..\SquirrelBusinessLogic\SquirrelBusinessLogic.csproj" />
     <ProjectReference Include="..\SquirrelContract\SquirrelContract.csproj" />
+    <ProjectReference Include="..\SquirrelDatabase\SquirrelDatabase.csproj" />
   </ItemGroup>
 
   <ItemGroup>

SquirrelContract/SquirrelTests/StorageContracts/BaseStorageContractTest.cs

@@ -0,0 +1,25 @@
+using SquirrelTests.Infrastructure;
+using SquirrelDatabase;
+
+namespace SquirrelTests.StoragesContracts;
+
+internal abstract class BaseStorageContractTest
+{
+	protected SquirrelDbContext SquirrelDbContext { get; private set; }
+
+	[OneTimeSetUp]
+	public void OneTimeSetUp()
+	{
+		SquirrelDbContext = new SquirrelDbContext(new ConfigurationDatabaseTest());
+
+		SquirrelDbContext.Database.EnsureDeleted();
+		SquirrelDbContext.Database.EnsureCreated();
+	}
+
+	[OneTimeTearDown]
+	public void OneTimeTearDown()
+	{
+		SquirrelDbContext.Database.EnsureDeleted();
+		SquirrelDbContext.Dispose();
+	}
+}

SquirrelContract/SquirrelTests/StorageContracts/ClientStorageContractTests.cs

@@ -0,0 +1,214 @@
+using SquirrelContract.DataModels;
+using SquirrelContract.Enums;
+using SquirrelContract.Exceptions;
+using SquirrelDatabase.Implementations;
+using SquirrelDatabase.Models;
+using Microsoft.EntityFrameworkCore;
+using SquirrelContract.StoragesContracts;
+using SquirrelTests.StoragesContracts;
+
+namespace SquirrelTests.StorageContracts;
+
+[TestFixture]
+internal class ClientStorageContractTests : BaseStorageContractTest
+{
+	private IClientStorageContract _clientStorageContract;
+
+	[SetUp]
+	public void SetUp()
+	{
+		_clientStorageContract = new ClientStorageContract(SquirrelDbContext);
+	}
+
+	[TearDown]
+	public void TearDown()
+	{
+        SquirrelDbContext.Database.ExecuteSqlRaw("TRUNCATE \"Sales\" CASCADE;");
+        SquirrelDbContext.Database.ExecuteSqlRaw("TRUNCATE \"Employees\" CASCADE;");
+        SquirrelDbContext.Database.ExecuteSqlRaw("TRUNCATE \"Clients\" CASCADE;");
+	}
+
+	[Test]
+	public void Try_GetList_WhenHaveRecords_Test()
+	{
+		var client = InsertClientToDatabaseAndReturn(Guid.NewGuid().ToString(), phoneNumber: "+5-555-555-55-55");
+		InsertClientToDatabaseAndReturn(Guid.NewGuid().ToString(), phoneNumber: "+6-666-666-66-66");
+		InsertClientToDatabaseAndReturn(Guid.NewGuid().ToString(), phoneNumber: "+7-777-777-77-77");
+		var list = _clientStorageContract.GetList();
+		Assert.That(list, Is.Not.Null);
+		Assert.That(list, Has.Count.EqualTo(3));
+		AssertElement(list.First(x => x.Id == client.Id), client);
+	}
+
+	[Test]
+	public void Try_GetList_WhenNoRecords_Test()
+	{
+		var list = _clientStorageContract.GetList();
+		Assert.That(list, Is.Not.Null);
+		Assert.That(list, Is.Empty);
+	}
+
+	[Test]
+	public void Try_GetElementById_WhenHaveRecord_Test()
+	{
+		var client = InsertClientToDatabaseAndReturn(Guid.NewGuid().ToString());
+		AssertElement(_clientStorageContract.GetElementById(client.Id), client);
+	}
+
+	[Test]
+	public void Try_GetElementById_WhenNoRecord_Test()
+	{
+		InsertClientToDatabaseAndReturn(Guid.NewGuid().ToString());
+		Assert.That(() => _clientStorageContract.GetElementById(Guid.NewGuid().ToString()), Is.Null);
+	}
+
+	[Test]
+	public void Try_GetElementByFIO_WhenHaveRecord_Test()
+	{
+		var client = InsertClientToDatabaseAndReturn(Guid.NewGuid().ToString());
+		AssertElement(_clientStorageContract.GetElementByFIO(client.FIO), client);
+	}
+
+	[Test]
+	public void Try_GetElementByFIO_WhenNoRecord_Test()
+	{
+		InsertClientToDatabaseAndReturn(Guid.NewGuid().ToString());
+		Assert.That(() => _clientStorageContract.GetElementByFIO("New Fio"), Is.Null);
+	}
+
+	[Test]
+	public void Try_GetElementByPhoneNumber_WhenHaveRecord_Test()
+	{
+		var client = InsertClientToDatabaseAndReturn(Guid.NewGuid().ToString());
+		AssertElement(_clientStorageContract.GetElementByPhoneNumber(client.PhoneNumber), client);
+	}
+
+	[Test]
+	public void Try_GetElementByPhoneNumber_WhenNoRecord_Test()
+	{
+		InsertClientToDatabaseAndReturn(Guid.NewGuid().ToString());
+		Assert.That(() => _clientStorageContract.GetElementByPhoneNumber("+8-888-888-88-88"), Is.Null);
+	}
+
+	[Test]
+	public void Try_AddElement_Test()
+	{
+		var client = CreateModel(Guid.NewGuid().ToString());
+		_clientStorageContract.AddElement(client);
+		AssertElement(GetClientFromDatabase(client.Id), client);
+	}
+
+	[Test]
+	public void Try_AddElement_WhenHaveRecordWithSameId_Test()
+	{
+		var client = CreateModel(Guid.NewGuid().ToString(), "New Fio", "+5-555-555-55-55", 500);
+		InsertClientToDatabaseAndReturn(client.Id);
+		Assert.That(() => _clientStorageContract.AddElement(client), Throws.TypeOf<ElementExistsException>());
+	}
+
+	[Test]
+	public void Try_AddElement_WhenHaveRecordWithSamePhoneNumber_Test()
+	{
+		var client = CreateModel(Guid.NewGuid().ToString(), "New Fio", "+5-555-555-55-55", 500);
+		InsertClientToDatabaseAndReturn(Guid.NewGuid().ToString(), phoneNumber: client.PhoneNumber);
+		Assert.That(() => _clientStorageContract.AddElement(client), Throws.TypeOf<ElementExistsException>());
+	}
+
+	[Test]
+	public void Try_UpdElement_Test()
+	{
+		var client = CreateModel(Guid.NewGuid().ToString(), "New Fio", "+5-555-555-55-55", 500);
+		InsertClientToDatabaseAndReturn(client.Id);
+		_clientStorageContract.UpdElement(client);
+		AssertElement(GetClientFromDatabase(client.Id), client);
+	}
+
+	[Test]
+	public void Try_UpdElement_WhenNoRecordWithThisId_Test()
+	{
+		Assert.That(() => _clientStorageContract.UpdElement(CreateModel(Guid.NewGuid().ToString())), Throws.TypeOf<ElementNotFoundException>());
+	}
+
+	[Test]
+	public void Try_UpdElement_WhenHaveRecordWithSamePhoneNumber_Test()
+	{
+		var client = CreateModel(Guid.NewGuid().ToString(), "New Fio", "+5-555-555-55-55", 500);
+		InsertClientToDatabaseAndReturn(client.Id, phoneNumber: "+7-777-777-77-77");
+		InsertClientToDatabaseAndReturn(Guid.NewGuid().ToString(), phoneNumber: client.PhoneNumber);
+		Assert.That(() => _clientStorageContract.UpdElement(client), Throws.TypeOf<ElementExistsException>());
+	}
+
+	[Test]
+	public void Try_DelElement_Test()
+	{
+		var client = InsertClientToDatabaseAndReturn(Guid.NewGuid().ToString());
+		_clientStorageContract.DelElement(client.Id);
+		var element = GetClientFromDatabase(client.Id);
+		Assert.That(element, Is.Null);
+	}
+
+	[Test]
+	public void Try_DelElement_WhenHaveSalesByThisClient_Test()
+	{
+		var client = InsertClientToDatabaseAndReturn(Guid.NewGuid().ToString());
+		var employeeId = Guid.NewGuid().ToString();
+		SquirrelDbContext.Employees.Add(new Employee() { Id = employeeId, FIO = "test", PostId = Guid.NewGuid().ToString(), Email = "abc@gmail.com" });
+		SquirrelDbContext.Sales.Add(new Sale() { Id = Guid.NewGuid().ToString(), EmployeeId = employeeId, ClientId = client.Id, Sum = 10, DiscountType = DiscountType.None, Discount = 0 });
+		SquirrelDbContext.Sales.Add(new Sale() { Id = Guid.NewGuid().ToString(), EmployeeId = employeeId, ClientId = client.Id, Sum = 10, DiscountType = DiscountType.None, Discount = 0 });
+		SquirrelDbContext.SaveChanges();
+		var salesBeforeDelete = SquirrelDbContext.Sales.Where(x => x.ClientId == client.Id).ToArray();
+		_clientStorageContract.DelElement(client.Id);
+		var element = GetClientFromDatabase(client.Id);
+		var salesAfterDelete = SquirrelDbContext.Sales.Where(x => x.ClientId == client.Id).ToArray();
+		Assert.Multiple(() =>
+		{
+			Assert.That(element, Is.Null);
+			Assert.That(salesBeforeDelete, Has.Length.EqualTo(2));
+			Assert.That(salesAfterDelete, Is.Empty);
+			Assert.That(SquirrelDbContext.Sales.Count(), Is.EqualTo(2));
+		});
+	}
+
+	[Test]
+	public void Try_DelElement_WhenNoRecordWithThisId_Test()
+	{
+		Assert.That(() => _clientStorageContract.DelElement(Guid.NewGuid().ToString()), Throws.TypeOf<ElementNotFoundException>());
+	}
+
+	private Client InsertClientToDatabaseAndReturn(string id, string fio = "test", string phoneNumber = "+7-777-777-77-77", double discountSize = 10)
+	{
+		var client = new Client() { Id = id, FIO = fio, PhoneNumber = phoneNumber, DiscountSize = discountSize };
+		SquirrelDbContext.Clients.Add(client);
+		SquirrelDbContext.SaveChanges();
+		return client;
+	}
+
+	private static void AssertElement(ClientDataModel? actual, Client expected)
+	{
+		Assert.That(actual, Is.Not.Null);
+		Assert.Multiple(() =>
+		{
+			Assert.That(actual.Id, Is.EqualTo(expected.Id));
+			Assert.That(actual.FIO, Is.EqualTo(expected.FIO));
+			Assert.That(actual.PhoneNumber, Is.EqualTo(expected.PhoneNumber));
+			Assert.That(actual.DiscountSize, Is.EqualTo(expected.DiscountSize));
+		});
+	}
+
+	private static ClientDataModel CreateModel(string id, string fio = "test", string phoneNumber = "+7-777-777-77-77", double discountSize = 10)
+		=> new(id, fio, phoneNumber, discountSize);
+
+	private Client? GetClientFromDatabase(string id) => SquirrelDbContext.Clients.FirstOrDefault(x => x.Id == id);
+
+	private static void AssertElement(Client? actual, ClientDataModel expected)
+	{
+		Assert.That(actual, Is.Not.Null);
+		Assert.Multiple(() =>
+		{
+			Assert.That(actual.Id, Is.EqualTo(expected.Id));
+			Assert.That(actual.FIO, Is.EqualTo(expected.FIO));
+			Assert.That(actual.PhoneNumber, Is.EqualTo(expected.PhoneNumber));
+			Assert.That(actual.DiscountSize, Is.EqualTo(expected.DiscountSize));
+		});
+	}
+}

SquirrelContract/SquirrelTests/StorageContracts/CocktailStorageContractTests.cs

@@ -0,0 +1,208 @@
+using Microsoft.EntityFrameworkCore;
+using SquirrelContract.DataModels;
+using SquirrelContract.Enums;
+using SquirrelContract.Exceptions;
+using SquirrelDatabase.Implementations;
+using SquirrelDatabase.Models;
+using SquirrelTests.StoragesContracts;
+using static NUnit.Framework.Internal.OSPlatform;
+
+namespace SquirrelTests.StorageContracts;
+
+[TestFixture]
+internal class CocktailStorageContractTests : BaseStorageContractTest
+{
+    private CocktailStorageContract _cocktailStorageContract;
+
+    [SetUp]
+    public void SetUp()
+    {
+        _cocktailStorageContract = new CocktailStorageContract(SquirrelDbContext);
+    }
+
+    [TearDown]
+    public void TearDown()
+    {
+        SquirrelDbContext.Database.ExecuteSqlRaw("TRUNCATE \"Cocktails\" CASCADE;");
+    }
+
+    [Test]
+    public void Try_GetList_WhenHaveRecords_Test()
+    {
+        var cocktail = InsertCocktailToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 1");
+        InsertCocktailToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 2");
+        InsertCocktailToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 3");
+        var list = _cocktailStorageContract.GetList();
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(3));
+        AssertElement(list.First(x => x.Id == cocktail.Id), cocktail);
+    }
+
+    [Test]
+    public void Try_GetList_WhenNoRecords_Test()
+    {
+        var list = _cocktailStorageContract.GetList();
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Is.Empty);
+    }
+
+    [Test]
+    public void Try_GetHistoryByCocktailId_WhenHaveRecords_Test()
+    {
+        var cocktail = InsertCocktailToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 1");
+        InsertCocktailHistoryToDatabaseAndReturn(cocktail.Id, 20, DateTime.UtcNow.AddDays(-1));
+        InsertCocktailHistoryToDatabaseAndReturn(cocktail.Id, 30, DateTime.UtcNow.AddMinutes(-10));
+        InsertCocktailHistoryToDatabaseAndReturn(cocktail.Id, 40, DateTime.UtcNow.AddDays(1));
+        var list = _cocktailStorageContract.GetHistoryByCocktailId(cocktail.Id);
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(3));
+    }
+
+    [Test]
+    public void Try_GetHistoryByCocktailId_WhenNoRecords_Test()
+    {
+        var cocktail = InsertCocktailToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 1");
+        InsertCocktailHistoryToDatabaseAndReturn(cocktail.Id, 20, DateTime.UtcNow.AddDays(-1));
+        InsertCocktailHistoryToDatabaseAndReturn(cocktail.Id, 30, DateTime.UtcNow.AddMinutes(-10));
+        InsertCocktailHistoryToDatabaseAndReturn(cocktail.Id, 40, DateTime.UtcNow.AddDays(1));
+        var list = _cocktailStorageContract.GetHistoryByCocktailId(Guid.NewGuid().ToString());
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(0));
+    }
+
+    [Test]
+    public void Try_GetElementById_WhenHaveRecord_Test()
+    {
+        var cocktail = InsertCocktailToDatabaseAndReturn(Guid.NewGuid().ToString());
+        AssertElement(_cocktailStorageContract.GetElementById(cocktail.Id), cocktail);
+    }
+
+    [Test]
+    public void Try_GetElementById_WhenNoRecord_Test()
+    {
+        InsertCocktailToDatabaseAndReturn(Guid.NewGuid().ToString());
+        Assert.That(() => _cocktailStorageContract.GetElementById(Guid.NewGuid().ToString()), Is.Null);
+    }
+
+    [Test]
+    public void Try_GetElementByName_WhenHaveRecord_Test()
+    {
+        var cocktail = InsertCocktailToDatabaseAndReturn(Guid.NewGuid().ToString());
+        AssertElement(_cocktailStorageContract.GetElementByName(cocktail.CocktailName), cocktail);
+    }
+
+    [Test]
+    public void Try_GetElementByName_WhenNoRecord_Test()
+    {
+        InsertCocktailToDatabaseAndReturn(Guid.NewGuid().ToString());
+        Assert.That(() => _cocktailStorageContract.GetElementByName("name"), Is.Null);
+    }
+
+    [Test]
+    public void Try_AddElement_Test()
+    {
+        var cocktail = CreateModel(Guid.NewGuid().ToString());
+        _cocktailStorageContract.AddElement(cocktail);
+        AssertElement(GetCocktailFromDatabaseById(cocktail.Id), cocktail);
+    }
+
+    [Test]
+    public void Try_AddElement_WhenHaveRecordWithSameId_Test()
+    {
+        var cocktail = CreateModel(Guid.NewGuid().ToString());
+        InsertCocktailToDatabaseAndReturn(cocktail.Id, cocktailName: "name unique");
+        Assert.That(() => _cocktailStorageContract.AddElement(cocktail), Throws.TypeOf<ElementExistsException>());
+    }
+
+    [Test]
+    public void Try_AddElement_WhenHaveRecordWithSameName_Test()
+    {
+        var cocktail = CreateModel(Guid.NewGuid().ToString(), "name unique");
+        InsertCocktailToDatabaseAndReturn(Guid.NewGuid().ToString(), cocktailName: cocktail.CocktailName);
+        Assert.That(() => _cocktailStorageContract.AddElement(cocktail), Throws.TypeOf<ElementExistsException>());
+    }
+
+    [Test]
+    public void Try_UpdElement_Test()
+    {
+        var cocktail = CreateModel(Guid.NewGuid().ToString(), "new name", AlcoholType.Vodka);
+        InsertCocktailToDatabaseAndReturn(cocktail.Id);
+        _cocktailStorageContract.UpdElement(cocktail);
+        AssertElement(GetCocktailFromDatabaseById(cocktail.Id), cocktail);
+    }
+
+    [Test]
+    public void Try_UpdElement_WhenNoRecordWithThisId_Test()
+    {
+        Assert.That(() => _cocktailStorageContract.UpdElement(CreateModel(Guid.NewGuid().ToString())), Throws.TypeOf<ElementNotFoundException>());
+    }
+
+    [Test]
+    public void Try_UpdElement_WhenHaveRecordWithSameName_Test()
+    {
+        var cocktail = CreateModel(Guid.NewGuid().ToString(), "name unique");
+        InsertCocktailToDatabaseAndReturn(cocktail.Id, cocktailName: "name");
+        InsertCocktailToDatabaseAndReturn(Guid.NewGuid().ToString(), cocktailName: cocktail.CocktailName);
+        Assert.That(() => _cocktailStorageContract.UpdElement(cocktail), Throws.TypeOf<ElementExistsException>());
+    }
+
+    [Test]
+    public void Try_DelElement_Test()
+    {
+        var cocktail = InsertCocktailToDatabaseAndReturn(Guid.NewGuid().ToString());
+        _cocktailStorageContract.DelElement(cocktail.Id);
+        var element = GetCocktailFromDatabaseById(cocktail.Id);
+        Assert.That(element, Is.Null);
+    }
+
+    [Test]
+    public void Try_DelElement_WhenNoRecordWithThisId_Test()
+    {
+        Assert.That(() => _cocktailStorageContract.DelElement(Guid.NewGuid().ToString()), Throws.TypeOf<ElementNotFoundException>());
+    }
+
+    private Cocktail InsertCocktailToDatabaseAndReturn(string id, string cocktailName = "test", AlcoholType baseAlcohol = AlcoholType.Vodka, double price = 1)
+    {
+        var cocktail = new Cocktail() { Id = id, CocktailName = cocktailName, BaseAlcohol = baseAlcohol, Price = price };
+        SquirrelDbContext.Cocktails.Add(cocktail);
+        SquirrelDbContext.SaveChanges();
+        return cocktail;
+    }
+
+    private CocktailHistory InsertCocktailHistoryToDatabaseAndReturn(string cocktailId, double price, DateTime changeDate)
+    {
+        var cocktailHistory = new CocktailHistory() { Id = Guid.NewGuid().ToString(), CocktailId = cocktailId, OldPrice = price, ChangeDate = changeDate };
+        SquirrelDbContext.CocktailHistories.Add(cocktailHistory);
+        SquirrelDbContext.SaveChanges();
+        return cocktailHistory;
+    }
+
+    private static void AssertElement(CocktailDataModel? actual, Cocktail expected)
+    {
+        Assert.That(actual, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(actual.Id, Is.EqualTo(expected.Id));
+            Assert.That(actual.CocktailName, Is.EqualTo(expected.CocktailName));
+            Assert.That(actual.BaseAlcohol, Is.EqualTo(expected.BaseAlcohol));
+            Assert.That(actual.Price, Is.EqualTo(expected.Price));
+        });
+    }
+
+    private static CocktailDataModel CreateModel(string id, string cocktailName = "test", AlcoholType baseAlcohol = AlcoholType.Beer, double price = 1)
+        => new(id, cocktailName, price, baseAlcohol);
+
+    private Cocktail? GetCocktailFromDatabaseById(string id) => SquirrelDbContext.Cocktails.FirstOrDefault(x => x.Id == id);
+
+    private static void AssertElement(Cocktail? actual, CocktailDataModel expected)
+    {
+        Assert.That(actual, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(actual.Id, Is.EqualTo(expected.Id));
+            Assert.That(actual.CocktailName, Is.EqualTo(expected.CocktailName));
+            Assert.That(actual.BaseAlcohol, Is.EqualTo(expected.BaseAlcohol));
+            Assert.That(actual.Price, Is.EqualTo(expected.Price));
+        });
+    }
+}

SquirrelContract/SquirrelTests/StorageContracts/EmployeeStorageContractTests.cs

@@ -0,0 +1,230 @@
+using Microsoft.EntityFrameworkCore;
+
+using SquirrelContract.Exceptions;
+using SquirrelDatabase.Implementations;
+using SquirrelDatabase.Models;
+using SquirrelContract.DataModels;
+using SquirrelTests.StoragesContracts;
+using System.ComponentModel.DataAnnotations;
+
+namespace SquirrelTests.StorageContracts;
+
+[TestFixture]
+internal class EmployeeStorageContractTests : BaseStorageContractTest
+{
+    private EmployeeStorageContract _employeeStorageContract;
+
+    [SetUp]
+    public void SetUp()
+    {
+        _employeeStorageContract = new EmployeeStorageContract(SquirrelDbContext);
+    }
+
+    [TearDown]
+    public void TearDown()
+    {
+        SquirrelDbContext.Database.ExecuteSqlRaw("TRUNCATE \"Employees\" CASCADE;");
+    }
+
+    [Test]
+    public void Try_GetList_WhenHaveRecords_Test()
+    {
+        var employee = InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 1", "abc@gmail.com");
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 2", "abc@gmail.com");
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 3", "abc@gmail.com");
+        var list = _employeeStorageContract.GetList();
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(3));
+        AssertElement(list.First(), employee);
+    }
+
+    [Test]
+    public void Try_GetList_WhenNoRecords_Test()
+    {
+        var list = _employeeStorageContract.GetList();
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Is.Empty);
+    }
+
+    [Test]
+    public void Try_GetList_ByPostId_Test()
+    {
+        var postId = Guid.NewGuid().ToString();
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 1", "abc@gmail.com", postId);
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 2", "abc@gmail.com", postId);
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 3", "abc@gmail.com");
+        var list = _employeeStorageContract.GetList(postId: postId);
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(2));
+        Assert.That(list.All(x => x.PostId == postId));
+    }
+
+    [Test]
+    public void Try_GetList_ByBirthDate_Test()
+    {
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 1", "abc@gmail.com", birthDate: DateTime.UtcNow.AddYears(-25));
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 2", "abc@gmail.com", birthDate: DateTime.UtcNow.AddYears(-21));
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 3", "abc@gmail.com", birthDate: DateTime.UtcNow.AddYears(-20));
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 4", "abc@gmail.com", birthDate: DateTime.UtcNow.AddYears(-19));
+        var list = _employeeStorageContract.GetList(fromBirthDate: DateTime.UtcNow.AddYears(-21).AddMinutes(-1), toBirthDate: DateTime.UtcNow.AddYears(-20).AddMinutes(1));
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(2));
+    }
+
+    [Test]
+    public void Try_GetList_ByEmploymentDate_Test()
+    {
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 1", "abc@gmail.com", employmentDate: DateTime.UtcNow.AddDays(-2));
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 2", "abc@gmail.com", employmentDate: DateTime.UtcNow.AddDays(-1));
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 3", "abc@gmail.com", employmentDate: DateTime.UtcNow.AddDays(1));
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 4", "abc@gmail.com", employmentDate: DateTime.UtcNow.AddDays(2));
+        var list = _employeeStorageContract.GetList(fromEmploymentDate: DateTime.UtcNow.AddDays(-1).AddMinutes(-1), toEmploymentDate: DateTime.UtcNow.AddDays(1).AddMinutes(1));
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(2));
+    }
+
+    [Test]
+    public void Try_GetList_ByAllParameters_Test()
+    {
+        var postId = Guid.NewGuid().ToString();
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 1", "abc@gmail.com", postId, birthDate: DateTime.UtcNow.AddYears(-25), employmentDate: DateTime.UtcNow.AddDays(-2));
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 2", "abc@gmail.com", postId, birthDate: DateTime.UtcNow.AddYears(-22), employmentDate: DateTime.UtcNow.AddDays(-1));
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 3", "abc@gmail.com", postId, birthDate: DateTime.UtcNow.AddYears(-21), employmentDate: DateTime.UtcNow.AddDays(-1));
+        InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString(), "fio 4", "abc@gmail.com", birthDate: DateTime.UtcNow.AddYears(-20), employmentDate: DateTime.UtcNow.AddDays(1));
+        var list = _employeeStorageContract.GetList(postId: postId, fromBirthDate: DateTime.UtcNow.AddYears(-21).AddMinutes(-1), toBirthDate: DateTime.UtcNow.AddYears(-20).AddMinutes(1), fromEmploymentDate: DateTime.UtcNow.AddDays(-1).AddMinutes(-1), toEmploymentDate: DateTime.UtcNow.AddDays(1).AddMinutes(1));
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(1));
+    }
+
+    [Test]
+    public void Try_GetElementById_WhenHaveRecord_Test()
+    {
+        var employee = InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString());
+        AssertElement(_employeeStorageContract.GetElementById(employee.Id), employee);
+    }
+
+    [Test]
+    public void Try_GetElementById_WhenNoRecord_Test()
+    {
+        Assert.That(() => _employeeStorageContract.GetElementById(Guid.NewGuid().ToString()), Is.Null);
+    }
+
+    [Test]
+    public void Try_GetElementByFIO_WhenHaveRecord_Test()
+    {
+        var employee = InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString());
+        AssertElement(_employeeStorageContract.GetElementByFIO(employee.FIO), employee);
+    }
+
+    [Test]
+    public void Try_GetElementByFIO_WhenNoRecord_Test()
+    {
+        Assert.That(() => _employeeStorageContract.GetElementByFIO("New Fio"), Is.Null);
+    }
+
+    [Test]
+    public void Try_AddElement_Test()
+    {
+        var employee = CreateModel(Guid.NewGuid().ToString());
+        _employeeStorageContract.AddElement(employee);
+        AssertElement(GetEmployeeFromDatabase(employee.Id), employee);
+    }
+
+    [Test]
+    public void Try_AddElement_WhenHaveRecordWithSameId_Test()
+    {
+        var employee = CreateModel(Guid.NewGuid().ToString());
+        InsertEmployeeToDatabaseAndReturn(employee.Id);
+        Assert.That(() => _employeeStorageContract.AddElement(employee), Throws.TypeOf<ElementExistsException>());
+    }
+
+    [Test]
+    public void Try_UpdElement_Test()
+    {
+        var employee = CreateModel(Guid.NewGuid().ToString(), "New Fio");
+        InsertEmployeeToDatabaseAndReturn(employee.Id);
+        _employeeStorageContract.UpdElement(employee);
+        AssertElement(GetEmployeeFromDatabase(employee.Id), employee);
+    }
+
+    [Test]
+    public void Try_UpdElement_WhenNoRecordWithThisId_Test()
+    {
+        Assert.That(() => _employeeStorageContract.UpdElement(CreateModel(Guid.NewGuid().ToString())), Throws.TypeOf<ElementNotFoundException>());
+    }
+
+    [Test]
+    public void Try_UpdElement_WhenNoRecordWasDeleted_Test()
+    {
+        var employee = CreateModel(Guid.NewGuid().ToString());
+        InsertEmployeeToDatabaseAndReturn(employee.Id, isDeleted: true);
+        Assert.That(() => _employeeStorageContract.UpdElement(employee), Throws.TypeOf<ElementNotFoundException>());
+    }
+
+    [Test]
+    public void Try_DelElement_Test()
+    {
+        var employee = InsertEmployeeToDatabaseAndReturn(Guid.NewGuid().ToString());
+        _employeeStorageContract.DelElement(employee.Id);
+        var element = GetEmployeeFromDatabase(employee.Id);
+        Assert.That(element, Is.Not.Null);
+        Assert.That(element.IsDeleted);
+    }
+
+    [Test]
+    public void Try_DelElement_WhenNoRecordWithThisId_Test()
+    {
+        Assert.That(() => _employeeStorageContract.DelElement(Guid.NewGuid().ToString()), Throws.TypeOf<ElementNotFoundException>());
+    }
+
+    [Test]
+    public void Try_DelElement_WhenNoRecordWasDeleted_Test()
+    {
+        var employee = CreateModel(Guid.NewGuid().ToString());
+        InsertEmployeeToDatabaseAndReturn(employee.Id, isDeleted: true);
+        Assert.That(() => _employeeStorageContract.DelElement(employee.Id), Throws.TypeOf<ElementNotFoundException>());
+    }
+
+    private Employee InsertEmployeeToDatabaseAndReturn(string id, string fio = "test", string email = "abc@mail.ru", string? postId = null, DateTime? birthDate = null, DateTime? employmentDate = null, bool isDeleted = false)
+    {
+        var employee = new Employee() { Id = id, FIO = fio, Email = email, PostId = postId ?? Guid.NewGuid().ToString(), BirthDate = birthDate ?? DateTime.UtcNow.AddYears(-20), EmploymentDate = employmentDate ?? DateTime.UtcNow, IsDeleted = isDeleted };
+        SquirrelDbContext.Employees.Add(employee);
+        SquirrelDbContext.SaveChanges();
+        return employee;
+    }
+
+    private static void AssertElement(EmployeeDataModel? actual, Employee expected)
+    {
+        Assert.That(actual, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(actual.Id, Is.EqualTo(expected.Id));
+            Assert.That(actual.PostId, Is.EqualTo(expected.PostId));
+            Assert.That(actual.FIO, Is.EqualTo(expected.FIO));
+            Assert.That(actual.Email, Is.EqualTo(expected.Email));
+            Assert.That(actual.BirthDate, Is.EqualTo(expected.BirthDate));
+            Assert.That(actual.EmploymentDate, Is.EqualTo(expected.EmploymentDate));
+            Assert.That(actual.IsDeleted, Is.EqualTo(expected.IsDeleted));
+        });
+    }
+
+    private static EmployeeDataModel CreateModel(string id, string fio = "fio", string email = "abc@mail.ru", string? postId = null, DateTime? birthDate = null, DateTime? employmentDate = null, bool isDeleted = false) =>
+        new(id, fio, email, postId ?? Guid.NewGuid().ToString(), birthDate ?? DateTime.UtcNow.AddYears(-20), employmentDate ?? DateTime.UtcNow, isDeleted);
+
+    private Employee? GetEmployeeFromDatabase(string id) => SquirrelDbContext.Employees.FirstOrDefault(x => x.Id == id);
+
+    private static void AssertElement(Employee? actual, EmployeeDataModel expected)
+    {
+        Assert.That(actual, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(actual.Id, Is.EqualTo(expected.Id));
+            Assert.That(actual.PostId, Is.EqualTo(expected.PostId));
+            Assert.That(actual.FIO, Is.EqualTo(expected.FIO));
+            Assert.That(actual.Email, Is.EqualTo(expected.Email));  
+            Assert.That(actual.BirthDate, Is.EqualTo(expected.BirthDate));
+            Assert.That(actual.EmploymentDate, Is.EqualTo(expected.EmploymentDate));
+            Assert.That(actual.IsDeleted, Is.EqualTo(expected.IsDeleted));
+        });
+    }
+}

SquirrelContract/SquirrelTests/StorageContracts/PostStorageContractTests.cs

@@ -0,0 +1,318 @@
+using Microsoft.EntityFrameworkCore;
+using SquirrelContract.DataModels;
+using SquirrelContract.Enums;
+using SquirrelContract.Exceptions;
+using SquirrelDatabase.Implementations;
+using SquirrelDatabase.Models;
+using SquirrelTests.StoragesContracts;
+
+namespace SquirrelTests.StorageContracts;
+
+[TestFixture]
+internal class PostStorageContractTests : BaseStorageContractTest
+{
+    private PostStorageContract _postStorageContract;
+
+    [SetUp]
+    public void SetUp()
+    {
+        _postStorageContract = new PostStorageContract(SquirrelDbContext);
+    }
+
+    [TearDown]
+    public void TearDown()
+    {
+        SquirrelDbContext.Database.ExecuteSqlRaw("TRUNCATE \"Posts\" CASCADE;");
+    }
+
+    [Test]
+    public void Try_GetList_WhenHaveRecords_Test()
+    {
+        var post = InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 1");
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 2");
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 3");
+        var list = _postStorageContract.GetList();
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(3));
+        AssertElement(list.First(x => x.Id == post.PostId), post);
+    }
+
+    [Test]
+    public void Try_GetList_WhenNoRecords_Test()
+    {
+        var list = _postStorageContract.GetList();
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Is.Empty);
+    }
+
+    [Test]
+    public void Try_GetList_OnlyActual_Test()
+    {
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 1", isActual: true);
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 2", isActual: true);
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 3", isActual: false);
+        var list = _postStorageContract.GetList(onlyActual: true);
+        Assert.That(list, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(list, Has.Count.EqualTo(2));
+            Assert.That(!list.Any(x => !x.IsActual));
+        });
+    }
+
+    [Test]
+    public void Try_GetList_IncludeNoActual_Test()
+    {
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 1", isActual: true);
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 2", isActual: true);
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 3", isActual: false);
+        var list = _postStorageContract.GetList(onlyActual: false);
+        Assert.That(list, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(list, Has.Count.EqualTo(3));
+            Assert.That(list.Count(x => x.IsActual), Is.EqualTo(2));
+            Assert.That(list.Count(x => !x.IsActual), Is.EqualTo(1));
+        });
+    }
+
+    [Test]
+    public void Try_GetPostWithHistory_WhenHaveRecords_Test()
+    {
+        var postId = Guid.NewGuid().ToString();
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 1", isActual: true);
+        InsertPostToDatabaseAndReturn(postId, "name 2", isActual: true);
+        InsertPostToDatabaseAndReturn(postId, "name 2", isActual: false);
+        var list = _postStorageContract.GetPostWithHistory(postId);
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(2));
+    }
+
+    [Test]
+    public void Try_GetPostWithHistory_WhenNoRecords_Test()
+    {
+        var postId = Guid.NewGuid().ToString();
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), "name 1", isActual: true);
+        InsertPostToDatabaseAndReturn(postId, "name 2", isActual: true);
+        InsertPostToDatabaseAndReturn(postId, "name 2", isActual: false);
+        var list = _postStorageContract.GetPostWithHistory(Guid.NewGuid().ToString());
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(0));
+    }
+
+    [Test]
+    public void Try_GetElementById_WhenHaveRecord_Test()
+    {
+        var post = InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString());
+        AssertElement(_postStorageContract.GetElementById(post.PostId), post);
+    }
+
+    [Test]
+    public void Try_GetElementById_WhenNoRecord_Test()
+    {
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString());
+        Assert.That(() => _postStorageContract.GetElementById(Guid.NewGuid().ToString()), Is.Null);
+    }
+
+    [Test]
+    public void Try_GetElementById_WhenRecordHasDeleted_Test()
+    {
+        var post = InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), isActual: false);
+        Assert.That(() => _postStorageContract.GetElementById(post.PostId), Is.Null);
+    }
+
+    [Test]
+    public void Try_GetElementById_WhenTrySearchById_Test()
+    {
+        var post = InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString());
+        Assert.That(() => _postStorageContract.GetElementById(post.Id), Is.Null);
+    }
+
+    [Test]
+    public void Try_GetElementByName_WhenHaveRecord_Test()
+    {
+        var post = InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString());
+        AssertElement(_postStorageContract.GetElementByName(post.PostName), post);
+    }
+
+    [Test]
+    public void Try_GetElementByName_WhenNoRecord_Test()
+    {
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString());
+        Assert.That(() => _postStorageContract.GetElementByName("name"), Is.Null);
+    }
+
+    [Test]
+    public void Try_GetElementByName_WhenRecordHasDeleted_Test()
+    {
+        var post = InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), isActual: false);
+        Assert.That(() => _postStorageContract.GetElementById(post.PostName), Is.Null);
+    }
+
+    [Test]
+    public void Try_AddElement_Test()
+    {
+        var post = CreateModel(Guid.NewGuid().ToString(), isActual: true);
+        _postStorageContract.AddElement(post);
+        AssertElement(GetPostFromDatabaseByPostId(post.Id), post);
+    }
+
+    [Test]
+    public void Try_AddElement_WhenActualIsFalse_Test()
+    {
+        var post = CreateModel(Guid.NewGuid().ToString(), isActual: false);
+        Assert.That(() => _postStorageContract.AddElement(post), Throws.Nothing);
+        AssertElement(GetPostFromDatabaseByPostId(post.Id), CreateModel(post.Id, isActual: true));
+    }
+
+    [Test]
+    public void Try_AddElement_WhenHaveRecordWithSameName_Test()
+    {
+        var post = CreateModel(Guid.NewGuid().ToString(), "name unique", isActual: true);
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), postName: post.PostName, isActual: true);
+        Assert.That(() => _postStorageContract.AddElement(post), Throws.TypeOf<ElementExistsException>());
+    }
+
+    [Test]
+    public void Try_AddElement_WhenHaveRecordWithSamePostIdAndActualIsTrue_Test()
+    {
+        var post = CreateModel(Guid.NewGuid().ToString(), isActual: true);
+        InsertPostToDatabaseAndReturn(post.Id, isActual: true);
+        Assert.That(() => _postStorageContract.AddElement(post), Throws.TypeOf<ElementExistsException>());
+    }
+
+    [Test]
+    public void Try_UpdElement_Test()
+    {
+        var post = CreateModel(Guid.NewGuid().ToString());
+        InsertPostToDatabaseAndReturn(post.Id, isActual: true);
+        _postStorageContract.UpdElement(post);
+        var posts = SquirrelDbContext.Posts.Where(x => x.PostId == post.Id).OrderByDescending(x => x.ChangeDate);
+        Assert.That(posts.Count(), Is.EqualTo(2));
+        AssertElement(posts.First(), CreateModel(post.Id, isActual: true));
+        AssertElement(posts.Last(), CreateModel(post.Id, isActual: false));
+    }
+
+    [Test]
+    public void Try_UpdElement_WhenActualIsFalse_Test()
+    {
+        var post = CreateModel(Guid.NewGuid().ToString(), isActual: false);
+        InsertPostToDatabaseAndReturn(post.Id, isActual: true);
+        _postStorageContract.UpdElement(post);
+        AssertElement(GetPostFromDatabaseByPostId(post.Id), CreateModel(post.Id, isActual: true));
+    }
+
+    [Test]
+    public void Try_UpdElement_WhenNoRecordWithThisId_Test()
+    {
+        Assert.That(() => _postStorageContract.UpdElement(CreateModel(Guid.NewGuid().ToString())), Throws.TypeOf<ElementNotFoundException>());
+    }
+
+    [Test]
+    public void Try_UpdElement_WhenHaveRecordWithSameName_Test()
+    {
+        var post = CreateModel(Guid.NewGuid().ToString(), "New Name");
+        InsertPostToDatabaseAndReturn(post.Id, postName: "name");
+        InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), postName: post.PostName);
+        Assert.That(() => _postStorageContract.UpdElement(post), Throws.TypeOf<ElementExistsException>());
+    }
+
+    [Test]
+    public void Try_UpdElement_WhenRecordWasDeleted_Test()
+    {
+        var post = CreateModel(Guid.NewGuid().ToString());
+        InsertPostToDatabaseAndReturn(post.Id, isActual: false);
+        Assert.That(() => _postStorageContract.UpdElement(post), Throws.TypeOf<ElementDeletedException>());
+    }
+
+    [Test]
+    public void Try_DelElement_Test()
+    {
+        var post = InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), isActual: true);
+        _postStorageContract.DelElement(post.PostId);
+        var element = GetPostFromDatabaseByPostId(post.PostId);
+        Assert.Multiple(() =>
+        {
+            Assert.That(element, Is.Not.Null);
+            Assert.That(!element!.IsActual);
+        });
+    }
+
+    [Test]
+    public void Try_DelElement_WhenNoRecordWithThisId_Test()
+    {
+        Assert.That(() => _postStorageContract.DelElement(Guid.NewGuid().ToString()), Throws.TypeOf<ElementNotFoundException>());
+    }
+
+    [Test]
+    public void Try_DelElement_WhenRecordWasDeleted_Test()
+    {
+        var post = InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), isActual: false);
+        Assert.That(() => _postStorageContract.DelElement(post.PostId), Throws.TypeOf<ElementDeletedException>());
+    }
+
+    [Test]
+    public void Try_ResElement_Test()
+    {
+        var post = InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), isActual: false);
+        _postStorageContract.ResElement(post.PostId);
+        var element = GetPostFromDatabaseByPostId(post.PostId);
+        Assert.Multiple(() =>
+        {
+            Assert.That(element, Is.Not.Null);
+            Assert.That(element!.IsActual);
+        });
+    }
+
+    [Test]
+    public void Try_ResElement_WhenNoRecordWithThisId_Test()
+    {
+        Assert.That(() => _postStorageContract.ResElement(Guid.NewGuid().ToString()), Throws.TypeOf<ElementNotFoundException>());
+    }
+
+    [Test]
+    public void Try_ResElement_WhenRecordNotWasDeleted_Test()
+    {
+        var post = InsertPostToDatabaseAndReturn(Guid.NewGuid().ToString(), isActual: true);
+        Assert.That(() => _postStorageContract.ResElement(post.PostId), Throws.Nothing);
+    }
+
+    private Post InsertPostToDatabaseAndReturn(string id, string postName = "test", PostType postType = PostType.Manager, double salary = 10, bool isActual = true, DateTime? changeDate = null)
+    {
+        var post = new Post() { Id = Guid.NewGuid().ToString(), PostId = id, PostName = postName, PostType = postType, Salary = salary, IsActual = isActual, ChangeDate = changeDate ?? DateTime.UtcNow };
+        SquirrelDbContext.Posts.Add(post);
+        SquirrelDbContext.SaveChanges();
+        return post;
+    }
+
+    private static void AssertElement(PostDataModel? actual, Post expected)
+    {
+        Assert.That(actual, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(actual.Id, Is.EqualTo(expected.PostId));
+            Assert.That(actual.PostName, Is.EqualTo(expected.PostName));
+            Assert.That(actual.PostType, Is.EqualTo(expected.PostType));
+            Assert.That(actual.Salary, Is.EqualTo(expected.Salary));
+            Assert.That(actual.IsActual, Is.EqualTo(expected.IsActual));
+        });
+    }
+
+    private static PostDataModel CreateModel(string postId, string postName = "test", PostType postType = PostType.Manager, double salary = 10, bool isActual = false, DateTime? changeDate = null)
+        => new(postId, postName, postType, salary, isActual, changeDate ?? DateTime.UtcNow);
+
+    private Post? GetPostFromDatabaseByPostId(string id) => SquirrelDbContext.Posts.Where(x => x.PostId == id).OrderByDescending(x => x.ChangeDate).FirstOrDefault();
+
+    private static void AssertElement(Post? actual, PostDataModel expected)
+    {
+        Assert.That(actual, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(actual.PostId, Is.EqualTo(expected.Id));
+            Assert.That(actual.PostName, Is.EqualTo(expected.PostName));
+            Assert.That(actual.PostType, Is.EqualTo(expected.PostType));
+            Assert.That(actual.Salary, Is.EqualTo(expected.Salary));
+            Assert.That(actual.IsActual, Is.EqualTo(expected.IsActual));
+        });
+    }
+}

SquirrelContract/SquirrelTests/StorageContracts/SalaryStorageContractTests.cs

@@ -0,0 +1,150 @@
+using BarBelochkaContract.DataModels;
+using Microsoft.EntityFrameworkCore;
+using SquirrelContract.StoragesContracts;
+using SquirrelDatabase.Implementations;
+using SquirrelDatabase.Models;
+using SquirrelTests.StoragesContracts;
+
+namespace SquirrelTests.StorageContracts;
+
+[TestFixture]
+internal class SalaryStorageContractTests : BaseStorageContractTest
+{
+    private SalaryStorageContract _salaryStorageContract;
+    private Employee _employee;
+
+    [SetUp]
+    public void SetUp()
+    {
+        _salaryStorageContract = new SalaryStorageContract(SquirrelDbContext);
+        _employee = InsertEmployeeToDatabaseAndReturn();
+    }
+
+    [TearDown]
+    public void TearDown()
+    {
+        SquirrelDbContext.Database.ExecuteSqlRaw("TRUNCATE \"Salaries\" CASCADE;");
+        SquirrelDbContext.Database.ExecuteSqlRaw("TRUNCATE \"Employees\" CASCADE;");
+    }
+
+    [Test]
+    public void Try_GetList_WhenHaveRecords_Test()
+    {
+        var salary = InsertSalaryToDatabaseAndReturn(_employee.Id, employeeSalary: 100);
+        InsertSalaryToDatabaseAndReturn(_employee.Id);
+        InsertSalaryToDatabaseAndReturn(_employee.Id);
+        var list = _salaryStorageContract.GetList(DateTime.UtcNow.AddDays(-10), DateTime.UtcNow.AddDays(10));
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(3));
+        AssertElement(list.First(), salary);
+    }
+
+    [Test]
+    public void Try_GetList_WhenNoRecords_Test()
+    {
+        var list = _salaryStorageContract.GetList(DateTime.UtcNow.AddDays(-10), DateTime.UtcNow.AddDays(10));
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Is.Empty);
+    }
+
+    [Test]
+    public void Try_GetList_OnlyInDatePeriod_Test()
+    {
+        InsertSalaryToDatabaseAndReturn(_employee.Id, salaryDate: DateTime.UtcNow.AddDays(-2));
+        InsertSalaryToDatabaseAndReturn(_employee.Id, salaryDate: DateTime.UtcNow.AddDays(-1).AddMinutes(-5));
+        InsertSalaryToDatabaseAndReturn(_employee.Id, salaryDate: DateTime.UtcNow.AddDays(-1).AddMinutes(5));
+        InsertSalaryToDatabaseAndReturn(_employee.Id, salaryDate: DateTime.UtcNow.AddDays(1).AddMinutes(-5));
+        InsertSalaryToDatabaseAndReturn(_employee.Id, salaryDate: DateTime.UtcNow.AddDays(1).AddMinutes(5));
+        InsertSalaryToDatabaseAndReturn(_employee.Id, salaryDate: DateTime.UtcNow.AddDays(-2));
+        var list = _salaryStorageContract.GetList(DateTime.UtcNow.AddDays(-1), DateTime.UtcNow.AddDays(1));
+        Assert.That(list, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(list, Has.Count.EqualTo(2));
+        });
+    }
+
+    [Test]
+    public void Try_GetList_ByEmployee_Test()
+    {
+        var employee = InsertEmployeeToDatabaseAndReturn("name 2");
+        InsertSalaryToDatabaseAndReturn(_employee.Id);
+        InsertSalaryToDatabaseAndReturn(_employee.Id);
+        InsertSalaryToDatabaseAndReturn(employee.Id);
+        var list = _salaryStorageContract.GetList(DateTime.UtcNow.AddDays(-1), DateTime.UtcNow.AddDays(1), _employee.Id);
+        Assert.That(list, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(list, Has.Count.EqualTo(2));
+            Assert.That(list.All(x => x.EmployeeId == _employee.Id));
+        });
+    }
+
+    [Test]
+    public void Try_GetList_ByEmployeeOnlyInDatePeriod_Test()
+    {
+        var employee = InsertEmployeeToDatabaseAndReturn("name 2");
+        InsertSalaryToDatabaseAndReturn(_employee.Id, salaryDate: DateTime.UtcNow.AddDays(-2));
+        InsertSalaryToDatabaseAndReturn(_employee.Id, salaryDate: DateTime.UtcNow.AddDays(-1).AddMinutes(5));
+        InsertSalaryToDatabaseAndReturn(employee.Id, salaryDate: DateTime.UtcNow.AddDays(-1).AddMinutes(5));
+        InsertSalaryToDatabaseAndReturn(_employee.Id, salaryDate: DateTime.UtcNow.AddDays(1).AddMinutes(-5));
+        InsertSalaryToDatabaseAndReturn(employee.Id, salaryDate: DateTime.UtcNow.AddDays(1).AddMinutes(-5));
+        InsertSalaryToDatabaseAndReturn(_employee.Id, salaryDate: DateTime.UtcNow.AddDays(-2));
+        var list = _salaryStorageContract.GetList(DateTime.UtcNow.AddDays(-1), DateTime.UtcNow.AddDays(1), _employee.Id);
+        Assert.That(list, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(list, Has.Count.EqualTo(2));
+            Assert.That(list.All(x => x.EmployeeId == _employee.Id));
+        });
+    }
+
+    [Test]
+    public void Try_AddElement_Test()
+    {
+        var salary = CreateModel(_employee.Id);
+        _salaryStorageContract.AddElement(salary);
+        AssertElement(GetSalaryFromDatabaseByEmployeeId(_employee.Id), salary);
+    }
+
+    private Employee InsertEmployeeToDatabaseAndReturn(string employeeFIO = "fio", string employeeEmail = "abc@mail.ru")
+    {
+        var employee = new Employee() { Id = Guid.NewGuid().ToString(), PostId = Guid.NewGuid().ToString(), FIO = employeeFIO, Email = employeeEmail, IsDeleted = false };
+        SquirrelDbContext.Employees.Add(employee);
+        SquirrelDbContext.SaveChanges();
+        return employee;
+    }
+
+    private Salary InsertSalaryToDatabaseAndReturn(string employeeId, double employeeSalary = 1, DateTime? salaryDate = null)
+    {
+        var salary = new Salary() { EmployeeId = employeeId, EmployeeSalary = employeeSalary, SalaryDate = salaryDate ?? DateTime.UtcNow };
+        SquirrelDbContext.Salaries.Add(salary);
+        SquirrelDbContext.SaveChanges();
+        return salary;
+    }
+
+    private static void AssertElement(SalaryDataModel? actual, Salary expected)
+    {
+        Assert.That(actual, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(actual.EmployeeId, Is.EqualTo(expected.EmployeeId));
+            Assert.That(actual.Salary, Is.EqualTo(expected.EmployeeSalary));
+        });
+    }
+
+    private static SalaryDataModel CreateModel(string employeeId, double employeeSalary = 1, DateTime? salaryDate = null)
+        => new(employeeId, salaryDate ?? DateTime.UtcNow, employeeSalary);
+
+    private Salary? GetSalaryFromDatabaseByEmployeeId(string id) => SquirrelDbContext.Salaries.FirstOrDefault(x => x.EmployeeId == id);
+
+    private static void AssertElement(Salary? actual, SalaryDataModel expected)
+    {
+        Assert.That(actual, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(actual.EmployeeId, Is.EqualTo(expected.EmployeeId));
+            Assert.That(actual.EmployeeSalary, Is.EqualTo(expected.Salary));
+        });
+    }
+}

SquirrelContract/SquirrelTests/StorageContracts/SaleStorageContractTests.cs

@@ -0,0 +1,303 @@
+using SquirrelContract.DataModels;
+using SquirrelContract.Enums;
+using SquirrelContract.Exceptions;
+using SquirrelDatabase.Implementations;
+using SquirrelDatabase.Models;
+using static NUnit.Framework.Internal.OSPlatform;
+using System;
+using SquirrelTests.StoragesContracts;
+using Microsoft.EntityFrameworkCore;
+
+namespace SquirrelTests.StorageContracts;
+
+[TestFixture]
+internal class SaleStorageContractTests : BaseStorageContractTest
+{
+    private SaleStorageContract _saleStorageContract;
+    private Client _client;
+    private Employee _employee;
+    private Cocktail _cocktail;
+
+    [SetUp]
+    public void SetUp()
+    {
+        _saleStorageContract = new SaleStorageContract(SquirrelDbContext);
+        _client = InsertClientToDatabaseAndReturn();
+        _employee = InsertEmployeeToDatabaseAndReturn();
+        _cocktail = InsertCocktailToDatabaseAndReturn();
+    }
+
+    [TearDown]
+    public void TearDown()
+    {
+        SquirrelDbContext.Database.ExecuteSqlRaw("TRUNCATE \"Sales\" CASCADE;");
+        SquirrelDbContext.Database.ExecuteSqlRaw("TRUNCATE \"Clients\" CASCADE;");
+        SquirrelDbContext.Database.ExecuteSqlRaw("TRUNCATE \"Employees\" CASCADE;");
+        SquirrelDbContext.Database.ExecuteSqlRaw("TRUNCATE \"Cocktails\" CASCADE;");
+    }
+
+    [Test]
+    public void Try_GetList_WhenHaveRecords_Test()
+    {
+        var sale = InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, cocktails: [(_cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, cocktails: [(_cocktail.Id, 5)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, null, cocktails: [(_cocktail.Id, 10)]);
+        var list = _saleStorageContract.GetList();
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(3));
+        AssertElement(list.First(x => x.Id == sale.Id), sale);
+    }
+
+    [Test]
+    public void Try_GetList_WhenNoRecords_Test()
+    {
+        var list = _saleStorageContract.GetList();
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Is.Empty);
+    }
+
+    [Test]
+    public void Try_GetList_ByPeriod_Test()
+    {
+        InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, saleDate: DateTime.UtcNow.AddDays(-1).AddMinutes(-3), cocktails: [(_cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, saleDate: DateTime.UtcNow.AddDays(-1).AddMinutes(3), cocktails: [(_cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, null, saleDate: DateTime.UtcNow.AddDays(1).AddMinutes(-3), cocktails: [(_cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, null, saleDate: DateTime.UtcNow.AddDays(1).AddMinutes(3), cocktails: [(_cocktail.Id, 1)]);
+        var list = _saleStorageContract.GetList(startDate: DateTime.UtcNow.AddDays(-1), endDate: DateTime.UtcNow.AddDays(1));
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(2));
+    }
+
+    [Test]
+    public void Try_GetList_ByEmployeeId_Test()
+    {
+        var employee = InsertEmployeeToDatabaseAndReturn("Other employee");
+        InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, cocktails: [(_cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, cocktails: [(_cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(employee.Id, null, cocktails: [(_cocktail.Id, 1)]);
+        var list = _saleStorageContract.GetList(employeeId: _employee.Id);
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(2));
+        Assert.That(list.All(x => x.EmployeeId == _employee.Id));
+    }
+
+    [Test]
+    public void Try_GetList_ByClientId_Test()
+    {
+        var client = InsertClientToDatabaseAndReturn("Other fio", "+8-888-888-88-88");
+        InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, cocktails: [(_cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, cocktails: [(_cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, client.Id, cocktails: [(_cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, null, cocktails: [(_cocktail.Id, 1)]);
+        var list = _saleStorageContract.GetList(clientId: _client.Id);
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(2));
+        Assert.That(list.All(x => x.ClientId == _client.Id));
+    }
+
+    [Test]
+    public void Try_GetList_ByCocktailId_Test()
+    {
+        var cocktail = InsertCocktailToDatabaseAndReturn("Other name");
+        InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, cocktails: [(_cocktail.Id, 5)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, cocktails: [(_cocktail.Id, 1), (cocktail.Id, 4)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, null, cocktails: [(cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, null, cocktails: [(cocktail.Id, 1), (_cocktail.Id, 1)]);
+        var list = _saleStorageContract.GetList(cocktailId: _cocktail.Id);
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(3));
+        Assert.That(list.All(x => x.Cocktails.Any(y => y.CocktailId == _cocktail.Id)));
+    }
+
+    [Test]
+    public void Try_GetList_ByAllParameters_Test()
+    {
+        var employee = InsertEmployeeToDatabaseAndReturn("Other employee");
+        var client = InsertClientToDatabaseAndReturn("Other fio", "+8-888-888-88-88");
+        var cocktail = InsertCocktailToDatabaseAndReturn("Other name");
+        InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, saleDate: DateTime.UtcNow.AddDays(-1).AddMinutes(-3), cocktails: [(_cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(employee.Id, null, saleDate: DateTime.UtcNow.AddDays(-1).AddMinutes(3), cocktails: [(_cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(employee.Id, _client.Id, saleDate: DateTime.UtcNow.AddDays(-1).AddMinutes(3), cocktails: [(_cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(employee.Id, _client.Id, saleDate: DateTime.UtcNow.AddDays(-1).AddMinutes(3), cocktails: [(cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, client.Id, saleDate: DateTime.UtcNow.AddDays(1).AddMinutes(-3), cocktails: [(_cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, saleDate: DateTime.UtcNow.AddDays(1).AddMinutes(-3), cocktails: [(cocktail.Id, 1)]);
+        InsertSaleToDatabaseAndReturn(employee.Id, null, saleDate: DateTime.UtcNow.AddDays(1).AddMinutes(-3), cocktails: [(_cocktail.Id, 1)]);
+        var list = _saleStorageContract.GetList(startDate: DateTime.UtcNow.AddDays(-1), endDate: DateTime.UtcNow.AddDays(1), employeeId: _employee.Id, clientId: _client.Id, cocktailId: cocktail.Id);
+        Assert.That(list, Is.Not.Null);
+        Assert.That(list, Has.Count.EqualTo(1));
+    }
+
+    [Test]
+    public void Try_GetElementById_WhenHaveRecord_Test()
+    {
+        var sale = InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, cocktails: [(_cocktail.Id, 1)]);
+        AssertElement(_saleStorageContract.GetElementById(sale.Id), sale);
+    }
+
+    [Test]
+    public void Try_GetElementById_WhenNoRecord_Test()
+    {
+        InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, cocktails: [(_cocktail.Id, 1)]);
+        Assert.That(() => _saleStorageContract.GetElementById(Guid.NewGuid().ToString()), Is.Null);
+    }
+
+    [Test]
+    public void Try_GetElementById_WhenRecordHasCanceled_Test()
+    {
+        var sale = InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, cocktails: [(_cocktail.Id, 1)], isCancel: true);
+        AssertElement(_saleStorageContract.GetElementById(sale.Id), sale);
+    }
+
+    [Test]
+    public void Try_AddElement_Test()
+    {
+        var sale = CreateModel(Guid.NewGuid().ToString(), _employee.Id, _client.Id, 1, DiscountType.RegularCustomer, 1, false, [_cocktail.Id]);
+        _saleStorageContract.AddElement(sale);
+        AssertElement(GetSaleFromDatabaseById(sale.Id), sale);
+    }
+
+    [Test]
+    public void Try_AddElement_WhenIsDeletedIsTrue_Test()
+    {
+        var sale = CreateModel(Guid.NewGuid().ToString(), _employee.Id, _client.Id, 1, DiscountType.RegularCustomer, 1, true, [_cocktail.Id]);
+        Assert.That(() => _saleStorageContract.AddElement(sale), Throws.Nothing);
+        AssertElement(GetSaleFromDatabaseById(sale.Id), CreateModel(sale.Id, _employee.Id, _client.Id, 1, DiscountType.RegularCustomer, 1, false, [_cocktail.Id]));
+    }
+
+    [Test]
+    public void Try_DelElement_Test()
+    {
+        var sale = InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, cocktails: [(_cocktail.Id, 1)], isCancel: false);
+        _saleStorageContract.DelElement(sale.Id);
+        var element = GetSaleFromDatabaseById(sale.Id);
+        Assert.Multiple(() =>
+        {
+            Assert.That(element, Is.Not.Null);
+            Assert.That(element!.IsCancel);
+        });
+    }
+
+    [Test]
+    public void Try_DelElement_WhenNoRecordWithThisId_Test()
+    {
+        Assert.That(() => _saleStorageContract.DelElement(Guid.NewGuid().ToString()), Throws.TypeOf<ElementNotFoundException>());
+    }
+
+    [Test]
+    public void Try_DelElement_WhenRecordWasCanceled_Test()
+    {
+        var sale = InsertSaleToDatabaseAndReturn(_employee.Id, _client.Id, cocktails: [(_cocktail.Id, 1)], isCancel: true);
+        Assert.That(() => _saleStorageContract.DelElement(sale.Id), Throws.TypeOf<ElementDeletedException>());
+    }
+
+    private Client InsertClientToDatabaseAndReturn(string fio = "test", string phoneNumber = "+7-777-777-77-77")
+    {
+        var client = new Client() { Id = Guid.NewGuid().ToString(), FIO = fio, PhoneNumber = phoneNumber, DiscountSize = 10 };
+        SquirrelDbContext.Clients.Add(client);
+        SquirrelDbContext.SaveChanges();
+        return client;
+    }
+
+    private Employee InsertEmployeeToDatabaseAndReturn(string fio = "test", string employeeEmail = "abc@gmail.com")
+    {
+        var employee = new Employee() { Id = Guid.NewGuid().ToString(), FIO = fio, Email = employeeEmail, PostId = Guid.NewGuid().ToString() };
+        SquirrelDbContext.Employees.Add(employee);
+        SquirrelDbContext.SaveChanges();
+        return employee;
+    }
+
+    private Cocktail InsertCocktailToDatabaseAndReturn(string cocktailName = "test", AlcoholType baseAlcohol = AlcoholType.Whiskey, double price = 1)
+    {
+        var cocktail = new Cocktail() { Id = Guid.NewGuid().ToString(), CocktailName = cocktailName, BaseAlcohol = baseAlcohol, Price = price };
+        SquirrelDbContext.Cocktails.Add(cocktail);
+        SquirrelDbContext.SaveChanges();
+        return cocktail;
+    }
+
+    private Sale InsertSaleToDatabaseAndReturn(string employeeId, string? clientId, DateTime? saleDate = null, double sum = 1, DiscountType discountType = DiscountType.OnSale, double discount = 0, bool isCancel = false, List<(string, int)>? cocktails = null)
+    {
+        var sale = new Sale() { EmployeeId = employeeId, ClientId = clientId, SaleDate = saleDate ?? DateTime.UtcNow, Sum = sum, DiscountType = discountType, Discount = discount, IsCancel = isCancel, SaleCocktails = [] };
+        if (cocktails is not null)
+        {
+            foreach (var elem in cocktails)
+            {
+                sale.SaleCocktails.Add(new SaleCocktail { CocktailId = elem.Item1, SaleId = sale.Id, Count = elem.Item2 });
+            }
+        }
+        SquirrelDbContext.Sales.Add(sale);
+        SquirrelDbContext.SaveChanges();
+        return sale;
+    }
+
+    private static void AssertElement(SaleDataModel? actual, Sale expected)
+    {
+        Assert.That(actual, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(actual.Id, Is.EqualTo(expected.Id));
+            Assert.That(actual.EmployeeId, Is.EqualTo(expected.EmployeeId));
+            Assert.That(actual.ClientId, Is.EqualTo(expected.ClientId));
+            Assert.That(actual.DiscountType, Is.EqualTo(expected.DiscountType));
+            Assert.That(actual.Discount, Is.EqualTo(expected.Discount));
+            Assert.That(actual.IsCancel, Is.EqualTo(expected.IsCancel));
+        });
+
+        if (expected.SaleCocktails is not null)
+        {
+            Assert.That(actual.Cocktails, Is.Not.Null);
+            Assert.That(actual.Cocktails, Has.Count.EqualTo(expected.SaleCocktails.Count));
+            for (int i = 0; i < actual.Cocktails.Count; ++i)
+            {
+                Assert.Multiple(() =>
+                {
+                    Assert.That(actual.Cocktails[i].CocktailId, Is.EqualTo(expected.SaleCocktails[i].CocktailId));
+                    Assert.That(actual.Cocktails[i].Count, Is.EqualTo(expected.SaleCocktails[i].Count));
+                });
+            }
+        }
+        else
+        {
+            Assert.That(actual.Cocktails, Is.Null);
+        }
+    }
+
+    private static SaleDataModel CreateModel(string id, string employeeId, string? clientId, double sum, DiscountType discountType, double discount, bool isCancel, List<string> cocktailIds)
+    {
+        var cocktails = cocktailIds.Select(x => new SaleCocktailDataModel(id, x, 1)).ToList();
+        return new(id, employeeId, clientId, sum, discountType, discount, isCancel, cocktails);
+    }
+
+    private Sale? GetSaleFromDatabaseById(string id) => SquirrelDbContext.Sales.Include(x => x.SaleCocktails).FirstOrDefault(x => x.Id == id);
+
+    private static void AssertElement(Sale? actual, SaleDataModel expected)
+    {
+        Assert.That(actual, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(actual.Id, Is.EqualTo(expected.Id));
+            Assert.That(actual.EmployeeId, Is.EqualTo(expected.EmployeeId));
+            Assert.That(actual.ClientId, Is.EqualTo(expected.ClientId));
+            Assert.That(actual.DiscountType, Is.EqualTo(expected.DiscountType));
+            Assert.That(actual.Discount, Is.EqualTo(expected.Discount));
+            Assert.That(actual.IsCancel, Is.EqualTo(expected.IsCancel));
+        });
+
+        if (expected.Cocktails is not null)
+        {
+            Assert.That(actual.SaleCocktails, Is.Not.Null);
+            Assert.That(actual.SaleCocktails, Has.Count.EqualTo(expected.Cocktails.Count));
+            for (int i = 0; i < actual.SaleCocktails.Count; ++i)
+            {
+                Assert.Multiple(() =>
+                {
+                    Assert.That(actual.SaleCocktails[i].CocktailId, Is.EqualTo(expected.Cocktails[i].CocktailId));
+                    Assert.That(actual.SaleCocktails[i].Count, Is.EqualTo(expected.Cocktails[i].Count));
+                });
+            }
+        }
+        else
+        {
+            Assert.That(actual.SaleCocktails, Is.Null);
+        }
+    }
+}