too much for one commit

tests/EntKube.Clusters.Tests/Features/GetClusterByIdHandlerTests.cs

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+using EntKube.Clusters.Domain;
+using EntKube.Clusters.Features.GetClusterById;
+using EntKube.Clusters.Infrastructure;
+using EntKube.SharedKernel.Domain;
+using FluentAssertions;
+
+namespace EntKube.Clusters.Tests.Features;
+
+public class GetClusterByIdHandlerTests
+{
+    private readonly GetClusterByIdHandler handler;
+    private readonly InMemoryClusterRepository repository;
+
+    public GetClusterByIdHandlerTests()
+    {
+        repository = new InMemoryClusterRepository();
+        handler = new GetClusterByIdHandler(repository);
+    }
+
+    [Fact]
+    public async Task HandleAsync_WithExistingCluster_ReturnsSuccess()
+    {
+        // Arrange — Register a cluster so the repository has something to find.
+
+        KubernetesCluster cluster = KubernetesCluster.Register(
+            "production-eu",
+            "https://k8s.example.com:6443",
+            "kubeconfig-data",
+            Guid.NewGuid(),
+            "prod-ctx", Guid.NewGuid());
+
+        await repository.AddAsync(cluster);
+
+        // Act — Look it up by its ID.
+
+        Result<KubernetesCluster> result = await handler.HandleAsync(cluster.Id);
+
+        // Assert — The handler should return the full cluster aggregate.
+
+        result.IsSuccess.Should().BeTrue();
+        result.Value.Should().NotBeNull();
+        result.Value!.Name.Should().Be("production-eu");
+    }
+
+    [Fact]
+    public async Task HandleAsync_WithNonExistentId_ReturnsFailure()
+    {
+        // Arrange — An ID that doesn't exist in the repository.
+
+        Guid unknownId = Guid.NewGuid();
+
+        // Act
+
+        Result<KubernetesCluster> result = await handler.HandleAsync(unknownId);
+
+        // Assert
+
+        result.IsFailure.Should().BeTrue();
+        result.Error.Should().Contain("not found");
+    }
+}