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.Provisioning.Tests/Domain/ServiceInstanceTests.cs

@@ -0,0 +1,79 @@
+using EntKube.Provisioning.Domain;
+using FluentAssertions;
+
+namespace EntKube.Provisioning.Tests.Domain;
+
+public class ServiceInstanceTests
+{
+    [Fact]
+    public void Provision_WithValidInputs_CreatesInstanceInPendingState()
+    {
+        // Arrange & Act — Request provisioning of a MinIO instance.
+
+        Guid clusterId = Guid.NewGuid();
+
+        ServiceInstance instance = ServiceInstance.Provision(
+            clusterId,
+            ServiceType.MinIO,
+            "tenant-storage",
+            "minio-system");
+
+        // Assert — Starts pending until the reconciler deploys it.
+
+        instance.Id.Should().NotBe(Guid.Empty);
+        instance.ClusterId.Should().Be(clusterId);
+        instance.ServiceType.Should().Be(ServiceType.MinIO);
+        instance.Name.Should().Be("tenant-storage");
+        instance.Namespace.Should().Be("minio-system");
+        instance.DesiredState.Should().Be(ServiceState.Running);
+        instance.CurrentState.Should().Be(ServiceState.Pending);
+    }
+
+    [Fact]
+    public void Provision_WithEmptyName_ThrowsArgumentException()
+    {
+        // Arrange & Act
+
+        Action act = () => ServiceInstance.Provision(Guid.NewGuid(), ServiceType.MinIO, "", "ns");
+
+        // Assert
+
+        act.Should().Throw<ArgumentException>()
+            .WithParameterName("name");
+    }
+
+    [Fact]
+    public void MarkRunning_UpdatesCurrentState()
+    {
+        // Arrange
+
+        ServiceInstance instance = ServiceInstance.Provision(Guid.NewGuid(), ServiceType.CloudNativePG, "db", "cnpg-system");
+
+        // Act
+
+        instance.MarkRunning();
+
+        // Assert
+
+        instance.CurrentState.Should().Be(ServiceState.Running);
+        instance.LastReconcileAt.Should().NotBeNull();
+    }
+
+    [Fact]
+    public void RequestDecommission_SetsDesiredStateToDecommissioned()
+    {
+        // Arrange
+
+        ServiceInstance instance = ServiceInstance.Provision(Guid.NewGuid(), ServiceType.Keycloak, "auth", "keycloak-system");
+        instance.MarkRunning();
+
+        // Act — Tenant admin decides to tear down this service.
+
+        instance.RequestDecommission();
+
+        // Assert — Desired state changes but current state remains until reconciler acts.
+
+        instance.DesiredState.Should().Be(ServiceState.Decommissioned);
+        instance.CurrentState.Should().Be(ServiceState.Running);
+    }
+}