client-go/features/testing: intro SetFeatureGatesDuringTest

Kubernetes-commit: 3d97808b95b355bb8e56d4d720342e9a7ab95ced

features/testing/features.go

@@ -0,0 +1,90 @@
+/*
+Copyright 2024 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package testing
+
+import (
+	"fmt"
+	"strings"
+	"sync"
+	"testing"
+
+	clientfeatures "k8s.io/client-go/features"
+)
+
+var (
+	overriddenFeaturesLock sync.Mutex
+	overriddenFeatures     map[clientfeatures.Feature]string
+)
+
+func init() {
+	overriddenFeatures = map[clientfeatures.Feature]string{}
+}
+
+type featureGatesSetter interface {
+	clientfeatures.Gates
+
+	Set(clientfeatures.Feature, bool) error
+}
+
+// SetFeatureDuringTest sets the specified feature to the specified value for the duration of the test.
+//
+// Example use:
+//
+//	clientfeaturestesting.SetFeatureDuringTest(t, clientfeatures.WatchListClient, true)
+func SetFeatureDuringTest(tb testing.TB, feature clientfeatures.Feature, featureValue bool) {
+	if err := setFeatureDuringTestInternal(tb, feature, featureValue); err != nil {
+		tb.Fatal(err)
+	}
+}
+
+func setFeatureDuringTestInternal(tb testing.TB, feature clientfeatures.Feature, featureValue bool) error {
+	overriddenFeaturesLock.Lock()
+	defer overriddenFeaturesLock.Unlock()
+
+	currentFeatureGates := clientfeatures.FeatureGates()
+	featureGates, ok := currentFeatureGates.(featureGatesSetter)
+	if !ok {
+		panic(fmt.Errorf("clientfeatures.FeatureGates(): %T does not implement featureGatesSetter interface", currentFeatureGates))
+	}
+
+	originalFeatureValue := featureGates.Enabled(feature)
+	if overridingTestName, ok := overriddenFeatures[feature]; ok {
+		if !sameTestOrSubtest(tb, overridingTestName) {
+			return fmt.Errorf("client-go feature %q is currently overridden by %q test and cannot be also modified by %q", feature, overridingTestName, tb.Name())
+		}
+	}
+
+	if err := featureGates.Set(feature, featureValue); err != nil {
+		return err
+	}
+	overriddenFeatures[feature] = tb.Name()
+
+	tb.Cleanup(func() {
+		overriddenFeaturesLock.Lock()
+		defer overriddenFeaturesLock.Unlock()
+		delete(overriddenFeatures, feature)
+		if err := featureGates.Set(feature, originalFeatureValue); err != nil {
+			tb.Errorf("failed restoring client-go feature: %v to its original value: %v, err: %v", feature, originalFeatureValue, err)
+		}
+	})
+	return nil
+}
+
+// copied from component-base/featuregate/testing
+func sameTestOrSubtest(tb testing.TB, testName string) bool {
+	return tb.Name() == testName || strings.HasPrefix(tb.Name(), testName+"/")
+}