Add unit tests for KubernetesCluster, Tenant, ServiceInstance, and RegisterClusterHandler

- Implement tests for KubernetesCluster including registration, connectivity status, and error handling.
- Create tests for Tenant creation, member management, and status changes.
- Add tests for ServiceInstance provisioning and state management.
- Introduce RegisterClusterHandler tests to validate registration requests and error scenarios.
- Set up project files for new test projects with necessary dependencies.

tests/EntKube.Identity.Tests/Domain/TenantTests.cs

@@ -0,0 +1,103 @@
+using EntKube.Identity.Domain;
+using FluentAssertions;
+
+namespace EntKube.Identity.Tests.Domain;
+
+public class TenantTests
+{
+    [Fact]
+    public void Create_WithValidInputs_CreatesTenantWithAdminMember()
+    {
+        // Arrange & Act — An admin creates a new tenant organization.
+
+        Guid userId = Guid.NewGuid();
+        Tenant tenant = Tenant.Create("Acme Corp", "acme-corp", userId);
+
+        // Assert — The tenant should be active and the creator should be admin.
+
+        tenant.Id.Should().NotBe(Guid.Empty);
+        tenant.Name.Should().Be("Acme Corp");
+        tenant.Slug.Should().Be("acme-corp");
+        tenant.Status.Should().Be(TenantStatus.Active);
+        tenant.Members.Should().HaveCount(1);
+        tenant.Members[0].UserId.Should().Be(userId);
+        tenant.Members[0].Role.Should().Be(TenantRole.Admin);
+    }
+
+    [Fact]
+    public void Create_WithEmptyName_ThrowsArgumentException()
+    {
+        // Arrange & Act
+
+        Action act = () => Tenant.Create("", "slug", Guid.NewGuid());
+
+        // Assert
+
+        act.Should().Throw<ArgumentException>()
+            .WithParameterName("name");
+    }
+
+    [Fact]
+    public void Create_WithEmptySlug_ThrowsArgumentException()
+    {
+        // Arrange & Act
+
+        Action act = () => Tenant.Create("Acme", "", Guid.NewGuid());
+
+        // Assert
+
+        act.Should().Throw<ArgumentException>()
+            .WithParameterName("slug");
+    }
+
+    [Fact]
+    public void AddMember_NewUser_AddsMemberToTenant()
+    {
+        // Arrange
+
+        Tenant tenant = Tenant.Create("Acme", "acme", Guid.NewGuid());
+        Guid newUserId = Guid.NewGuid();
+
+        // Act
+
+        tenant.AddMember(newUserId, TenantRole.Member);
+
+        // Assert
+
+        tenant.Members.Should().HaveCount(2);
+        tenant.Members.Should().Contain(m => m.UserId == newUserId && m.Role == TenantRole.Member);
+    }
+
+    [Fact]
+    public void AddMember_ExistingUser_DoesNotDuplicate()
+    {
+        // Arrange — Create a tenant (creator is already a member).
+
+        Guid userId = Guid.NewGuid();
+        Tenant tenant = Tenant.Create("Acme", "acme", userId);
+
+        // Act — Try adding the same user again.
+
+        tenant.AddMember(userId, TenantRole.Viewer);
+
+        // Assert — Still only one member.
+
+        tenant.Members.Should().HaveCount(1);
+    }
+
+    [Fact]
+    public void Suspend_SetsStatusToSuspended()
+    {
+        // Arrange
+
+        Tenant tenant = Tenant.Create("Acme", "acme", Guid.NewGuid());
+
+        // Act
+
+        tenant.Suspend();
+
+        // Assert
+
+        tenant.Status.Should().Be(TenantStatus.Suspended);
+    }
+}