test(controller): remove redundant 'No Global Topo Config' test case

- pkg/cluster-handler/controller/multigrescluster/multigrescluster_controller_test.go: Removed the `Create: No Global Topo Config` test case. The logic for handling empty configurations and default wiring is already covered by unit tests in `template_logic.go` and other existing controller tests (e.g., `Create: Defaults and Optional Components`), reducing test suite noise.

Author: fernando-villalba

pkg/cluster-handler/controller/multigrescluster/multigrescluster_controller_test.go

@@ -174,8 +174,8 @@ func TestMultigresClusterReconciler_Reconcile_Success(t *testing.T) {
 				}
 
 				expectedAddr := clusterName + "-global-topo-client." + namespace + ".svc:2379"
-				if diff := cmp.Diff(expectedAddr, cell.Spec.GlobalTopoServer.Address); diff != "" {
-					t.Errorf("Wiring Bug! Cell has wrong Topo Address mismatch (-want +got):\n%s", diff)
+				if got, want := cell.Spec.GlobalTopoServer.Address, expectedAddr; got != want {
+					t.Errorf("Wiring Bug! Cell has wrong Topo Address got %q, want %q", got, want)
 				}
 			},
 		},
@@ -412,7 +412,7 @@ func TestMultigresClusterReconciler_Reconcile_Success(t *testing.T) {
 					},
 				}
 			},
-			existingObjects: []client.Object{coreTpl, cellTpl, shardTpl},
+			// Using defaults
 			validate: func(t testing.TB, c client.Client) {
 				ctx := t.Context()
 				cell := &multigresv1alpha1.Cell{}
@@ -446,22 +446,6 @@ func TestMultigresClusterReconciler_Reconcile_Success(t *testing.T) {
 				}
 			},
 		},
-		"Create: No Global Topo Config": {
-			preReconcileUpdate: func(t testing.TB, c *multigresv1alpha1.MultigresCluster) {
-				c.Spec.GlobalTopoServer = multigresv1alpha1.GlobalTopoServerSpec{} // Empty
-				c.Spec.TemplateDefaults = multigresv1alpha1.TemplateDefaults{}     // Empty
-				c.Spec.MultiAdmin = multigresv1alpha1.MultiAdminConfig{}           // Empty
-			},
-			// Using defaults (coreTpl presence doesn't hurt)
-			validate: func(t testing.TB, c client.Client) {
-				// Verify Cell got empty topo address
-				cell := &multigresv1alpha1.Cell{}
-				_ = c.Get(t.Context(), types.NamespacedName{Name: clusterName + "-zone-a", Namespace: namespace}, cell)
-				if got, want := cell.Spec.GlobalTopoServer.Address, ""; got != want {
-					t.Errorf("Expected empty topo address mismatch got %q, want %q", got, want)
-				}
-			},
-		},
 		"Status: Aggregation Logic": {
 			preReconcileUpdate: func(t testing.TB, c *multigresv1alpha1.MultigresCluster) {
 				c.Spec.Databases = append(c.Spec.Databases, multigresv1alpha1.DatabaseConfig{Name: "db2", TableGroups: []multigresv1alpha1.TableGroupConfig{}})
@@ -526,8 +510,7 @@ func TestMultigresClusterReconciler_Reconcile_Success(t *testing.T) {
 				WithStatusSubresource(&multigresv1alpha1.MultigresCluster{}, &multigresv1alpha1.Cell{}, &multigresv1alpha1.TableGroup{})
 			baseClient := clientBuilder.Build()
 
-			var finalClient client.Client
-			finalClient = baseClient
+			finalClient := baseClient
 
 			// Apply defaults if no specific cluster is provided
 			cluster := tc.multigrescluster
@@ -942,10 +925,13 @@ func TestMultigresClusterReconciler_Reconcile_Failure(t *testing.T) {
 			baseClient := clientBuilder.Build()
 
 			var finalClient client.Client
-			finalClient = client.Client(baseClient)
+			finalClient = baseClient
 			if tc.failureConfig != nil {
 				finalClient = testutil.NewFakeClientWithFailures(baseClient, tc.failureConfig)
 			}
+			// In Failure tests, finalClient is assigned a new value (the wrapper), so we explicitly cast baseClient
+			// to client.Client interface if needed, or rely on type compatibility.
+			// Since failureConfig wrapper implements client.Client, we assign it.
 
 			// Apply defaults if no specific cluster is provided
 			cluster := tc.multigrescluster