AllowVolumeExpansion validation and tests

Signed-off-by: Serguei Bezverkhi <sbezverk@cisco.com>

pkg/apis/storage/util/util_test.go

@@ -17,9 +17,11 @@ limitations under the License.
 package util
 
 import (
+	"fmt"
 	"reflect"
 	"testing"
 
+	"k8s.io/apimachinery/pkg/util/diff"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	utilfeaturetesting "k8s.io/apiserver/pkg/util/feature/testing"
 	api "k8s.io/kubernetes/pkg/apis/core"
@@ -68,3 +70,82 @@ func TestDropAlphaFields(t *testing.T) {
 		t.Errorf("AllowedTopologies field got unexpectantly modified: %+v", class.AllowedTopologies)
 	}
 }
+
+func TestDropAllowVolumeExpansion(t *testing.T) {
+	allowVolumeExpansion := false
+	scWithoutAllowVolumeExpansion := func() *storage.StorageClass {
+		return &storage.StorageClass{}
+	}
+	scWithAllowVolumeExpansion := func() *storage.StorageClass {
+		return &storage.StorageClass{
+			AllowVolumeExpansion: &allowVolumeExpansion,
+		}
+	}
+
+	scInfo := []struct {
+		description             string
+		hasAllowVolumeExpansion bool
+		sc                      func() *storage.StorageClass
+	}{
+		{
+			description:             "StorageClass Without AllowVolumeExpansion",
+			hasAllowVolumeExpansion: false,
+			sc:                      scWithoutAllowVolumeExpansion,
+		},
+		{
+			description:             "StorageClass With AllowVolumeExpansion",
+			hasAllowVolumeExpansion: true,
+			sc:                      scWithAllowVolumeExpansion,
+		},
+		{
+			description:             "is nil",
+			hasAllowVolumeExpansion: false,
+			sc:                      func() *storage.StorageClass { return nil },
+		},
+	}
+
+	for _, enabled := range []bool{true, false} {
+		for _, oldStorageClassInfo := range scInfo {
+			for _, newStorageClassInfo := range scInfo {
+				oldStorageClassHasAllowVolumeExpansion, oldStorageClass := oldStorageClassInfo.hasAllowVolumeExpansion, oldStorageClassInfo.sc()
+				newStorageClassHasAllowVolumeExpansion, newStorageClass := newStorageClassInfo.hasAllowVolumeExpansion, newStorageClassInfo.sc()
+				if newStorageClass == nil {
+					continue
+				}
+
+				t.Run(fmt.Sprintf("feature enabled=%v, old StorageClass %v, new StorageClass %v", enabled, oldStorageClassInfo.description, newStorageClassInfo.description), func(t *testing.T) {
+					defer utilfeaturetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.ExpandPersistentVolumes, enabled)()
+
+					DropDisabledFields(newStorageClass, oldStorageClass)
+
+					// old StorageClass should never be changed
+					if !reflect.DeepEqual(oldStorageClass, oldStorageClassInfo.sc()) {
+						t.Errorf("old StorageClass changed: %v", diff.ObjectReflectDiff(oldStorageClass, oldStorageClassInfo.sc()))
+					}
+
+					switch {
+					case enabled || oldStorageClassHasAllowVolumeExpansion:
+						// new StorageClass should not be changed if the feature is enabled, or if the old StorageClass had AllowVolumeExpansion
+						if !reflect.DeepEqual(newStorageClass, newStorageClassInfo.sc()) {
+							t.Errorf("new StorageClass changed: %v", diff.ObjectReflectDiff(newStorageClass, newStorageClassInfo.sc()))
+						}
+					case newStorageClassHasAllowVolumeExpansion:
+						// new StorageClass should be changed
+						if reflect.DeepEqual(newStorageClass, newStorageClassInfo.sc()) {
+							t.Errorf("new StorageClass was not changed")
+						}
+						// new StorageClass should not have AllowVolumeExpansion
+						if !reflect.DeepEqual(newStorageClass, scWithoutAllowVolumeExpansion()) {
+							t.Errorf("new StorageClass had StorageClassAllowVolumeExpansion: %v", diff.ObjectReflectDiff(newStorageClass, scWithoutAllowVolumeExpansion()))
+						}
+					default:
+						// new StorageClass should not need to be changed
+						if !reflect.DeepEqual(newStorageClass, newStorageClassInfo.sc()) {
+							t.Errorf("new StorageClass changed: %v", diff.ObjectReflectDiff(newStorageClass, newStorageClassInfo.sc()))
+						}
+					}
+				})
+			}
+		}
+	}
+}