diff --git a/TheCyclopsProject/TheCyclopsProject.sln b/TheCyclopsProject/TheCyclopsProject.sln
index 0fc1d92..4fa5a94 100644
--- a/TheCyclopsProject/TheCyclopsProject.sln
+++ b/TheCyclopsProject/TheCyclopsProject.sln
@@ -5,6 +5,8 @@ VisualStudioVersion = 17.12.35707.178 d17.12
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TheCyclopsContracts", "TheCyclopsContracts\TheCyclopsContracts.csproj", "{01934235-715E-4B95-B859-48E8C89DA7CB}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TheCyclopsTests", "TheCyclopsTests\TheCyclopsTests.csproj", "{78C9F1B1-ABD3-4ED2-A5DC-84766DEEFC77}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -15,6 +17,10 @@ Global
 		{01934235-715E-4B95-B859-48E8C89DA7CB}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{01934235-715E-4B95-B859-48E8C89DA7CB}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{01934235-715E-4B95-B859-48E8C89DA7CB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{78C9F1B1-ABD3-4ED2-A5DC-84766DEEFC77}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{78C9F1B1-ABD3-4ED2-A5DC-84766DEEFC77}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{78C9F1B1-ABD3-4ED2-A5DC-84766DEEFC77}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{78C9F1B1-ABD3-4ED2-A5DC-84766DEEFC77}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
diff --git a/TheCyclopsProject/TheCyclopsTests/DataModelsTests/ClientDataModelTests.cs b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/ClientDataModelTests.cs
new file mode 100644
index 0000000..886ea3a
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/ClientDataModelTests.cs
@@ -0,0 +1,73 @@
+using TheCyclopsContracts.DataModels;
+using TheCyclopsContracts.Exceptions;
+
+namespace TheCyclopsTests.DataModelsTests;
+
+[TestFixture]
+internal class ClientDataModelTests
+{
+    [Test]
+    public void IdIsNullOrEmptyTest()
+    {
+        var client = CreateDataModel(null, "fio", "email");
+        Assert.That(() => client.Validate(), Throws.TypeOf<ValidationException>());
+
+        client = CreateDataModel(string.Empty, "fio", "email");
+        Assert.That(() => client.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void IdIsNotGuidTest()
+    {
+        var client = CreateDataModel("id", "fio", "email");
+        Assert.That(() => client.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void FIOIsNullOrEmptyTest()
+    {
+        var client = CreateDataModel(Guid.NewGuid().ToString(), null, "email");
+        Assert.That(() => client.Validate(), Throws.TypeOf<ValidationException>());
+
+        client = CreateDataModel(Guid.NewGuid().ToString(), string.Empty, "email");
+        Assert.That(() => client.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void EmailIsNullOrEmptyTest()
+    {
+        var client = CreateDataModel(Guid.NewGuid().ToString(), "fio", null);
+        Assert.That(() => client.Validate(), Throws.TypeOf<ValidationException>());
+
+        client = CreateDataModel(Guid.NewGuid().ToString(), "fio", string.Empty);
+        Assert.That(() => client.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void EmailIsIncorrectTest()
+    {
+        var client = CreateDataModel(Guid.NewGuid().ToString(), "fio", "email");
+        Assert.That(() => client.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void AllFieldsIsCorrectTest()
+    {
+        var clientId = Guid.NewGuid().ToString();
+        var fio = "Fio";
+        var email = "email.email@email.com";
+        var client = CreateDataModel(clientId, fio, email);
+
+        Assert.That(() => client.Validate(), Throws.Nothing);
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(client.Id, Is.EqualTo(clientId));
+            Assert.That(client.FIO, Is.EqualTo(fio));
+            Assert.That(client.Email, Is.EqualTo(email));
+        });
+    }
+
+    private static ClientDataModel CreateDataModel(string? id, string? fio, string? email) =>
+        new(id, fio, email);
+}
diff --git a/TheCyclopsProject/TheCyclopsTests/DataModelsTests/ComponentDataModelTests.cs b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/ComponentDataModelTests.cs
new file mode 100644
index 0000000..f0c233a
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/ComponentDataModelTests.cs
@@ -0,0 +1,80 @@
+using TheCyclopsContracts.DataModels;
+using TheCyclopsContracts.Enums;
+using TheCyclopsContracts.Exceptions;
+
+namespace TheCyclopsTests.DataModelsTests;
+
+[TestFixture]
+internal class ComponentDataModelTests
+{
+    [Test]
+    public void IdIsNullOrEmptyTest()
+    {
+        var component = CreateDataModel(null, "name", ComponentType.Other, 10, false);
+        Assert.That(() => component.Validate(), Throws.TypeOf<ValidationException>());
+
+        component = CreateDataModel(string.Empty, "name", ComponentType.Other, 10, false);
+        Assert.That(() => component.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void IdIsNotGuidTest()
+    {
+        var component = CreateDataModel("id", "name", ComponentType.Other, 10, false);
+        Assert.That(() => component.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void ProductNameIsEmptyTest()
+    {
+        var component = CreateDataModel(Guid.NewGuid().ToString(), null, ComponentType.Other, 10, false);
+        Assert.That(() => component.Validate(), Throws.TypeOf<ValidationException>());
+
+        component = CreateDataModel(Guid.NewGuid().ToString(), string.Empty, ComponentType.Other, 10, false);
+        Assert.That(() => component.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void ComponentTypeIsNoneTest()
+    {
+        var component = CreateDataModel(Guid.NewGuid().ToString(), null, ComponentType.None, 10, false);
+        Assert.That(() => component.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void PriceIsLessOrZeroTest()
+    {
+        var component = CreateDataModel(Guid.NewGuid().ToString(), "name", ComponentType.Other, 0, false);
+        Assert.That(() => component.Validate(), Throws.TypeOf<ValidationException>());
+
+        component = CreateDataModel(Guid.NewGuid().ToString(), "name", ComponentType.Other, -10, false);
+        Assert.That(() => component.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void AllFieldsIsCorrectTest()
+    {
+        var componentId = Guid.NewGuid().ToString();
+        var componentName = "name";
+        var componentType = ComponentType.Other;
+        var componentManufacturerId = Guid.NewGuid().ToString();
+        var componentPrice = 10;
+        var componentIsDelete = false;
+        var component = CreateDataModel(componentId, componentName, componentType, componentPrice, componentIsDelete);
+
+        Assert.That(() => component.Validate(), Throws.Nothing);
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(component.Id, Is.EqualTo(componentId));
+            Assert.That(component.ComponentName, Is.EqualTo(componentName));
+            Assert.That(component.ComponentType, Is.EqualTo(componentType));
+            Assert.That(component.Price, Is.EqualTo(componentPrice));
+            Assert.That(component.IsDeleted, Is.EqualTo(componentIsDelete));
+        });
+    }
+
+    private static ComponentDataModel CreateDataModel(string? id, string? componentName,
+        ComponentType componentType, double price, bool isDeleted) =>
+        new(id, componentName, componentType, price, isDeleted);
+}
diff --git a/TheCyclopsProject/TheCyclopsTests/DataModelsTests/EmployeeDataModelTests.cs b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/EmployeeDataModelTests.cs
new file mode 100644
index 0000000..24d7b12
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/EmployeeDataModelTests.cs
@@ -0,0 +1,108 @@
+using TheCyclopsContracts.DataModels;
+using TheCyclopsContracts.Exceptions;
+
+namespace TheCyclopsTests.DataModelsTests;
+
+[TestFixture]
+internal class EmployeeDataModelTests
+{
+    [Test]
+    public void IdIsNullOrEmptyTest()
+    {
+        var employee = CreateDataModel(null, "fio", Guid.NewGuid().ToString(),
+            DateTime.Now.AddYears(-18), DateTime.Now, false);
+        Assert.That(() => employee.Validate(), Throws.TypeOf<ValidationException>());
+
+        employee = CreateDataModel(string.Empty, "fio", Guid.NewGuid().ToString(),
+            DateTime.Now.AddYears(-18), DateTime.Now, false);
+        Assert.That(() => employee.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void IdIsNotGuidTest()
+    {
+        var employee = CreateDataModel("id", "fio", Guid.NewGuid().ToString(),
+            DateTime.Now.AddYears(-18), DateTime.Now, false);
+        Assert.That(() => employee.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void FIOIsNullOrEmptyTest()
+    {
+        var employee = CreateDataModel(Guid.NewGuid().ToString(), null, Guid.NewGuid().ToString(),
+            DateTime.Now.AddYears(-18), DateTime.Now, false);
+        Assert.That(() => employee.Validate(), Throws.TypeOf<ValidationException>());
+
+        employee = CreateDataModel(Guid.NewGuid().ToString(), string.Empty, Guid.NewGuid().ToString(),
+            DateTime.Now.AddYears(-18), DateTime.Now, false);
+        Assert.That(() => employee.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void PostIdIsNullOrEmptyTest()
+    {
+        var employee = CreateDataModel(Guid.NewGuid().ToString(), "fio", null,
+            DateTime.Now.AddYears(-18), DateTime.Now, false);
+        Assert.That(() => employee.Validate(), Throws.TypeOf<ValidationException>());
+
+        employee = CreateDataModel(Guid.NewGuid().ToString(), "fio", string.Empty,
+            DateTime.Now.AddYears(-18), DateTime.Now, false);
+        Assert.That(() => employee.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void PostIdIsNotGuidTest()
+    {
+        var employee = CreateDataModel(Guid.NewGuid().ToString(), "fio", "postId",
+            DateTime.Now.AddYears(-18), DateTime.Now, false);
+        Assert.That(() => employee.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void BirthDateIsNotCorrectTest()
+    {
+        var employee = CreateDataModel(Guid.NewGuid().ToString(), "fio", Guid.NewGuid().ToString(),
+            DateTime.Now.AddYears(-16).AddDays(1), DateTime.Now, false);
+        Assert.That(() => employee.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void BirthDateAndEmploymentDateIsNotCorrectTest()
+    {
+        var employee = CreateDataModel(Guid.NewGuid().ToString(), "fio", Guid.NewGuid().ToString(),
+            DateTime.Now.AddYears(-18), DateTime.Now.AddYears(-18).AddDays(-1), false);
+        Assert.That(() => employee.Validate(), Throws.TypeOf<ValidationException>());
+
+        employee = CreateDataModel(Guid.NewGuid().ToString(), "fio", Guid.NewGuid().ToString(),
+            DateTime.Now.AddYears(-18), DateTime.Now.AddYears(-16), false);
+        Assert.That(() => employee.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void AllFieldsIsCorrectTest()
+    {
+        var employeeId = Guid.NewGuid().ToString();
+        var fio = "fio";
+        var postId = Guid.NewGuid().ToString();
+        var birthDate = DateTime.Now.AddYears(-16).AddDays(-1);
+        var employmentDate = DateTime.Now;
+        var isDeleted = false;
+        var employee = CreateDataModel(employeeId, fio, postId, birthDate, employmentDate, isDeleted);
+
+        Assert.That(() => employee.Validate(), Throws.Nothing);
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(employee.Id, Is.EqualTo(employeeId));
+            Assert.That(employee.FIO, Is.EqualTo(fio));
+            Assert.That(employee.PostId, Is.EqualTo(postId));
+            Assert.That(employee.BirthDate, Is.EqualTo(birthDate));
+            Assert.That(employee.EmploymentDate, Is.EqualTo(employmentDate));
+            Assert.That(employee.IsDeleted, Is.EqualTo(isDeleted));
+        });
+    }
+
+    private static EmployeeDataModel CreateDataModel(string? id, string? fio, string? postId,
+        DateTime birthDate, DateTime employmentDate, bool isDeleted) =>
+        new(id, fio, postId, birthDate, employmentDate, isDeleted);
+}
diff --git a/TheCyclopsProject/TheCyclopsTests/DataModelsTests/InstallationComponentDataModelTests.cs b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/InstallationComponentDataModelTests.cs
new file mode 100644
index 0000000..6b55343
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/InstallationComponentDataModelTests.cs
@@ -0,0 +1,73 @@
+using TheCyclopsContracts.DataModels;
+using TheCyclopsContracts.Exceptions;
+
+namespace TheCyclopsTests.DataModelsTests;
+
+[TestFixture]
+internal class InstallationComponentDataModelTests
+{
+    [Test]
+    public void InstallationIdIsNullOrEmptyTest()
+    {
+        var saleProduct = CreateDataModel(null, Guid.NewGuid().ToString(), 10);
+        Assert.That(() => saleProduct.Validate(), Throws.TypeOf<ValidationException>());
+
+        saleProduct = CreateDataModel(string.Empty, Guid.NewGuid().ToString(), 10);
+        Assert.That(() => saleProduct.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void InstallationIdIsNotGuidTest()
+    {
+        var saleProduct = CreateDataModel("installationId", Guid.NewGuid().ToString(), 10);
+        Assert.That(() => saleProduct.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void ComponentIdIsNullOrEmptyTest()
+    {
+        var saleProduct = CreateDataModel(Guid.NewGuid().ToString(), null, 10);
+        Assert.That(() => saleProduct.Validate(), Throws.TypeOf<ValidationException>());
+
+        saleProduct = CreateDataModel(string.Empty, Guid.NewGuid().ToString(), 10);
+        Assert.That(() => saleProduct.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void ComponentIdIsNotGuidTest()
+    {
+        var saleProduct = CreateDataModel(Guid.NewGuid().ToString(), "componentId", 10);
+        Assert.That(() => saleProduct.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void CountIsLessOrZeroTest()
+    {
+        var saleProduct = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 0);
+        Assert.That(() => saleProduct.Validate(), Throws.TypeOf<ValidationException>());
+
+        saleProduct = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), -10);
+        Assert.That(() => saleProduct.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void AllFieldsIsCorrectTest()
+    {
+        var installationId = Guid.NewGuid().ToString();
+        var componentId = Guid.NewGuid().ToString();
+        var count = 10;
+        var saleProduct = CreateDataModel(installationId, componentId, count);
+
+        Assert.That(() => saleProduct.Validate(), Throws.Nothing);
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(saleProduct.InstallationId, Is.EqualTo(installationId));
+            Assert.That(saleProduct.ComponentId, Is.EqualTo(componentId));
+            Assert.That(saleProduct.Count, Is.EqualTo(count));
+        });
+    }
+
+    private static InstallationComponentDataModel CreateDataModel(string? installationId, string? componentId, int count) =>
+        new(installationId, componentId, count);
+}
diff --git a/TheCyclopsProject/TheCyclopsTests/DataModelsTests/InstallationDataModelTests.cs b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/InstallationDataModelTests.cs
new file mode 100644
index 0000000..71289f9
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/InstallationDataModelTests.cs
@@ -0,0 +1,126 @@
+using TheCyclopsContracts.DataModels;
+using TheCyclopsContracts.Exceptions;
+
+namespace TheCyclopsTests.DataModelsTests;
+
+[TestFixture]
+internal class InstallationDataModelTests
+{
+    [Test]
+    public void IdIsNullOrEmptyTest()
+    {
+        var installation = CreateDataModel(null, Guid.NewGuid().ToString(), Guid.NewGuid().ToString(),
+            DateTime.UtcNow, 10, 20, false, CreateSubDataModel());
+        Assert.That(() => installation.Validate(), Throws.TypeOf<ValidationException>());
+
+        installation = CreateDataModel(string.Empty, Guid.NewGuid().ToString(), Guid.NewGuid().ToString(),
+            DateTime.UtcNow, 10, 20, false, CreateSubDataModel());
+        Assert.That(() => installation.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void IdIsNotGuidTest()
+    {
+        var installation = CreateDataModel("id", Guid.NewGuid().ToString(), Guid.NewGuid().ToString(),
+            DateTime.UtcNow, 10, 20, false, CreateSubDataModel());
+        Assert.That(() => installation.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void EmployeeIdIsNullOrEmptyTest()
+    {
+        var installation = CreateDataModel(Guid.NewGuid().ToString(), null, Guid.NewGuid().ToString(),
+            DateTime.UtcNow, 10, 20, false, CreateSubDataModel());
+        Assert.That(() => installation.Validate(), Throws.TypeOf<ValidationException>());
+
+        installation = CreateDataModel(Guid.NewGuid().ToString(), string.Empty, Guid.NewGuid().ToString(),
+            DateTime.UtcNow, 10, 20, false, CreateSubDataModel());
+        Assert.That(() => installation.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void EmployeeIdIsNotGuidTest()
+    {
+        var installation = CreateDataModel(Guid.NewGuid().ToString(), "employeeId", Guid.NewGuid().ToString(),
+            DateTime.UtcNow, 10, 20, false, CreateSubDataModel());
+        Assert.That(() => installation.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void ClientIdIsNotGuidTest()
+    {
+        var installation = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), "buyerId",
+            DateTime.UtcNow, 10, 20, false, CreateSubDataModel());
+        Assert.That(() => installation.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void InstallationPriceIsLessOrZeroTest()
+    {
+        var installation = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), "buyerId",
+            DateTime.UtcNow, 0, 20, false, CreateSubDataModel());
+        Assert.That(() => installation.Validate(), Throws.TypeOf<ValidationException>());
+
+        installation = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), "buyerId",
+            DateTime.UtcNow, -10, 20, false, CreateSubDataModel());
+        Assert.That(() => installation.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void SumIsLessOrZeroTest()
+    {
+        var installation = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), "buyerId",
+            DateTime.UtcNow, 10, 0, false, CreateSubDataModel());
+        Assert.That(() => installation.Validate(), Throws.TypeOf<ValidationException>());
+
+        installation = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), "buyerId",
+            DateTime.UtcNow, 10, -20, false, CreateSubDataModel());
+        Assert.That(() => installation.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void ProductsIsNullOrEmptyTest()
+    {
+        var installation = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), "buyerId",
+            DateTime.UtcNow, 10, 20, false, null);
+        Assert.That(() => installation.Validate(), Throws.TypeOf<ValidationException>());
+
+        installation = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), "buyerId",
+            DateTime.UtcNow, 10, 20, false, []);
+        Assert.That(() => installation.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void AllFieldsIsCorrectTest()
+    {
+        var installationId = Guid.NewGuid().ToString();
+        var employeeId = Guid.NewGuid().ToString();
+        var client = Guid.NewGuid().ToString();
+        var installationPrice = 10;
+        var sum = 20;
+        var isCanceled = true;
+        var components = CreateSubDataModel();
+        var installation = CreateDataModel(installationId, employeeId, client,
+            DateTime.UtcNow, installationPrice, sum, isCanceled, components);
+
+        Assert.That(() => installation.Validate(), Throws.Nothing);
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(installation.Id, Is.EqualTo(installationId));
+            Assert.That(installation.EmployeeId, Is.EqualTo(employeeId));
+            Assert.That(installation.ClientId, Is.EqualTo(client));
+            Assert.That(installation.Sum, Is.EqualTo(sum));
+            Assert.That(installation.IsCanceled, Is.EqualTo(isCanceled));
+            Assert.That(installation.Components, Is.EquivalentTo(components));
+        });
+    }
+
+    private static InstallationDataModel CreateDataModel(string id, string employeeId, string? clientId,
+        DateTime installationDate, double installationPrice, double sum, bool isCanceled,
+        List<InstallationComponentDataModel> components) =>
+        new(id, employeeId, clientId, installationDate, installationPrice, sum, isCanceled, components);
+
+    private static List<InstallationComponentDataModel> CreateSubDataModel()
+        => [new(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), 1)];
+}
diff --git a/TheCyclopsProject/TheCyclopsTests/DataModelsTests/PostDataModelTests.cs b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/PostDataModelTests.cs
new file mode 100644
index 0000000..d942348
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/PostDataModelTests.cs
@@ -0,0 +1,110 @@
+using TheCyclopsContracts.DataModels;
+using TheCyclopsContracts.Enums;
+using TheCyclopsContracts.Exceptions;
+
+namespace TheCyclopsTests.DataModelsTests;
+
+[TestFixture]
+internal class PostDataModelTests
+{
+    [Test]
+    public void IdIsNullOrEmptyTest()
+    {
+        var post = CreateDataModel(null, Guid.NewGuid().ToString(), "post",
+            PostType.Designer, 10, true, DateTime.UtcNow);
+        Assert.That(() => post.Validate(), Throws.TypeOf<ValidationException>());
+
+        post = CreateDataModel(string.Empty, Guid.NewGuid().ToString(), "post",
+            PostType.Designer, 10, true, DateTime.UtcNow);
+        Assert.That(() => post.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void IdIsNotGuidTest()
+    {
+        var post = CreateDataModel("id", Guid.NewGuid().ToString(), "post",
+            PostType.Designer, 10, true, DateTime.UtcNow);
+        Assert.That(() => post.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void PostIdIsNullEmptyTest()
+    {
+        var post = CreateDataModel(Guid.NewGuid().ToString(), null, "post",
+            PostType.Designer, 10, true, DateTime.UtcNow);
+        Assert.That(() => post.Validate(), Throws.TypeOf<ValidationException>());
+
+        post = CreateDataModel(Guid.NewGuid().ToString(), string.Empty, "post",
+            PostType.Designer, 10, true, DateTime.UtcNow);
+        Assert.That(() => post.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void PostIdIsNotGuidTest()
+    {
+        var post = CreateDataModel(Guid.NewGuid().ToString(), "postId", "post",
+            PostType.Designer, 10, true, DateTime.UtcNow);
+        Assert.That(() => post.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void PostNameIsEmptyTest()
+    {
+        var manufacturer = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), null,
+            PostType.Designer, 10, true, DateTime.UtcNow);
+        Assert.That(() => manufacturer.Validate(), Throws.TypeOf<ValidationException>());
+
+        manufacturer = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), string.Empty,
+            PostType.Designer, 10, true, DateTime.UtcNow);
+        Assert.That(() => manufacturer.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void PostTypeIsNoneTest()
+    {
+        var post = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), "post",
+            PostType.None, 10, true, DateTime.UtcNow);
+        Assert.That(() => post.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void SalaryIsLessOrZeroTest()
+    {
+        var post = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), "post",
+            PostType.Designer, 0, true, DateTime.UtcNow);
+        Assert.That(() => post.Validate(), Throws.TypeOf<ValidationException>());
+
+        post = CreateDataModel(Guid.NewGuid().ToString(), Guid.NewGuid().ToString(), "post",
+            PostType.Designer, -10, true, DateTime.UtcNow);
+        Assert.That(() => post.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void AllFieldsIsCorrectTest()
+    {
+        var postId = Guid.NewGuid().ToString();
+        var postPostId = Guid.NewGuid().ToString();
+        var postName = "name";
+        var postType = PostType.Designer;
+        var salary = 10;
+        var isActual = false;
+        var changeDate = DateTime.UtcNow.AddDays(-1);
+        var post = CreateDataModel(postId, postPostId, postName, postType, salary, isActual, changeDate);
+
+        Assert.That(() => post.Validate(), Throws.Nothing);
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(post.Id, Is.EqualTo(postId));
+            Assert.That(post.PostId, Is.EqualTo(postPostId));
+            Assert.That(post.PostName, Is.EqualTo(postName));
+            Assert.That(post.PostType, Is.EqualTo(postType));
+            Assert.That(post.Salary, Is.EqualTo(salary));
+            Assert.That(post.IsActual, Is.EqualTo(isActual));
+            Assert.That(post.ChangeDate, Is.EqualTo(changeDate));
+        });
+    }
+
+    private static PostDataModel CreateDataModel(string? id, string? postId, string? postName, PostType postType, double salary, bool isActual, DateTime changeDate) =>
+        new(id, postId, postName, postType, salary, isActual, changeDate);
+}
diff --git a/TheCyclopsProject/TheCyclopsTests/DataModelsTests/SalaryDataModelTests.cs b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/SalaryDataModelTests.cs
new file mode 100644
index 0000000..bb63037
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsTests/DataModelsTests/SalaryDataModelTests.cs
@@ -0,0 +1,56 @@
+using TheCyclopsContracts.DataModels;
+using TheCyclopsContracts.Exceptions;
+
+namespace TheCyclopsTests.DataModelsTests;
+
+[TestFixture]
+internal class SalaryDataModelTests
+{
+    [Test]
+    public void WorkerIdIsEmptyTest()
+    {
+        var salary = CreateDataModel(null, DateTime.Now, 10);
+        Assert.That(() => salary.Validate(), Throws.TypeOf<ValidationException>());
+
+        salary = CreateDataModel(string.Empty, DateTime.Now, 10);
+        Assert.That(() => salary.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void WorkerIdIsNotGuidTest()
+    {
+        var salary = CreateDataModel("employeeId", DateTime.Now, 10);
+        Assert.That(() => salary.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void PriceIsLessOrZeroTest()
+    {
+        var salary = CreateDataModel(Guid.NewGuid().ToString(), DateTime.Now, 0);
+        Assert.That(() => salary.Validate(), Throws.TypeOf<ValidationException>());
+
+        salary = CreateDataModel(Guid.NewGuid().ToString(), DateTime.Now, -10);
+        Assert.That(() => salary.Validate(), Throws.TypeOf<ValidationException>());
+    }
+
+    [Test]
+    public void AllFieldsIsCorrectTest()
+    {
+        var employeeId = Guid.NewGuid().ToString();
+        var salaryDate = DateTime.Now.AddDays(-3).AddMinutes(-5);
+        var employeeSalary = 10;
+        var salary = CreateDataModel(employeeId, salaryDate, employeeSalary);
+
+        Assert.That(() => salary.Validate(), Throws.Nothing);
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(salary.EmployeeId, Is.EqualTo(employeeId));
+            Assert.That(salary.SalaryDate, Is.EqualTo(salaryDate));
+            Assert.That(salary.Salary, Is.EqualTo(employeeSalary));
+        });
+    }
+
+    private static SalaryDataModel CreateDataModel(string? employeeId, DateTime salaryDate, double workerSalary) =>
+        new(employeeId, salaryDate, workerSalary);
+}
diff --git a/TheCyclopsProject/TheCyclopsTests/TheCyclopsTests.csproj b/TheCyclopsProject/TheCyclopsTests/TheCyclopsTests.csproj
new file mode 100644
index 0000000..349b926
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsTests/TheCyclopsTests.csproj
@@ -0,0 +1,27 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <LangVersion>latest</LangVersion>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.2" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
+    <PackageReference Include="NUnit" Version="4.2.2" />
+    <PackageReference Include="NUnit.Analyzers" Version="4.4.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.6.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\TheCyclopsContracts\TheCyclopsContracts.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="NUnit.Framework" />
+  </ItemGroup>
+
+</Project>