storage: enhance test for ValidateCSIDriverUpdate

This revised test changes one field at a time in various ways. This
ensures that one failure reason doesn't mask the other.

An incorrect comment also gets fixed.

Suggested in kubernetes#80568 (review).

pkg/apis/storage/validation/validation_test.go

@@ -1800,7 +1800,7 @@ func TestCSIDriverValidation(t *testing.T) {
 			},
 		},
 		{
-			// AttachRequired not set
+			// PodInfoOnMount not set
 			ObjectMeta: metav1.ObjectMeta{Name: driverName},
 			Spec: storage.CSIDriverSpec{
 				AttachRequired: &attachNotRequired,
@@ -1856,64 +1856,86 @@ func TestCSIDriverValidationUpdate(t *testing.T) {
 		}
 	}
 
-	errorCases := []storage.CSIDriver{
+	// Each test case changes exactly one field. None of that is valid.
+	errorCases := []struct {
+		name   string
+		modify func(new *storage.CSIDriver)
+	}{
 		{
-			ObjectMeta: metav1.ObjectMeta{Name: invalidName},
-			Spec: storage.CSIDriverSpec{
-				AttachRequired: &attachRequired,
-				PodInfoOnMount: &podInfoOnMount,
+			name: "invalid name",
+			modify: func(new *storage.CSIDriver) {
+				new.Name = invalidName
 			},
 		},
 		{
-			ObjectMeta: metav1.ObjectMeta{Name: longName},
-			Spec: storage.CSIDriverSpec{
-				AttachRequired: &attachNotRequired,
-				PodInfoOnMount: &notPodInfoOnMount,
+			name: "long name",
+			modify: func(new *storage.CSIDriver) {
+				new.Name = longName
 			},
 		},
 		{
-			// AttachRequired not set
-			ObjectMeta: metav1.ObjectMeta{Name: driverName},
-			Spec: storage.CSIDriverSpec{
-				AttachRequired: nil,
-				PodInfoOnMount: &podInfoOnMount,
+			name: "AttachRequired not set",
+			modify: func(new *storage.CSIDriver) {
+				new.Spec.AttachRequired = nil
 			},
 		},
 		{
-			// AttachRequired not set
-			ObjectMeta: metav1.ObjectMeta{Name: driverName},
-			Spec: storage.CSIDriverSpec{
-				AttachRequired: &attachNotRequired,
-				PodInfoOnMount: nil,
+			name: "PodInfoOnMount not set",
+			modify: func(new *storage.CSIDriver) {
+				new.Spec.PodInfoOnMount = nil
 			},
 		},
 		{
-			// invalid mode
-			ObjectMeta: metav1.ObjectMeta{Name: driverName},
-			Spec: storage.CSIDriverSpec{
-				AttachRequired: &attachNotRequired,
-				PodInfoOnMount: &notPodInfoOnMount,
-				VolumeLifecycleModes: []storage.VolumeLifecycleMode{
+			name: "AttachRequired changed",
+			modify: func(new *storage.CSIDriver) {
+				new.Spec.AttachRequired = &attachRequired
+			},
+		},
+		{
+			name: "PodInfoOnMount changed",
+			modify: func(new *storage.CSIDriver) {
+				new.Spec.PodInfoOnMount = &podInfoOnMount
+			},
+		},
+		{
+			name: "invalid volume lifecycle mode",
+			modify: func(new *storage.CSIDriver) {
+				new.Spec.VolumeLifecycleModes = []storage.VolumeLifecycleMode{
 					"no-such-mode",
-				},
+				}
 			},
 		},
 		{
-			// different modes
-			ObjectMeta: metav1.ObjectMeta{Name: driverName},
-			Spec: storage.CSIDriverSpec{
-				AttachRequired: &attachNotRequired,
-				PodInfoOnMount: &notPodInfoOnMount,
-				VolumeLifecycleModes: []storage.VolumeLifecycleMode{
+			name: "volume lifecycle modes not set",
+			modify: func(new *storage.CSIDriver) {
+				new.Spec.VolumeLifecycleModes = nil
+			},
+		},
+		{
+			name: "VolumeLifecyclePersistent removed",
+			modify: func(new *storage.CSIDriver) {
+				new.Spec.VolumeLifecycleModes = []storage.VolumeLifecycleMode{
 					storage.VolumeLifecycleEphemeral,
-				},
+				}
+			},
+		},
+		{
+			name: "VolumeLifecycleEphemeral removed",
+			modify: func(new *storage.CSIDriver) {
+				new.Spec.VolumeLifecycleModes = []storage.VolumeLifecycleMode{
+					storage.VolumeLifecyclePersistent,
+				}
 			},
 		},
 	}
 
-	for _, csiDriver := range errorCases {
-		if errs := ValidateCSIDriverUpdate(&csiDriver, &old); len(errs) == 0 {
-			t.Errorf("Expected failure for test: %v", csiDriver)
-		}
+	for _, test := range errorCases {
+		t.Run(test.name, func(t *testing.T) {
+			new := old.DeepCopy()
+			test.modify(new)
+			if errs := ValidateCSIDriverUpdate(new, &old); len(errs) == 0 {
+				t.Errorf("Expected failure for test: %v", new)
+			}
+		})
 	}
 }