Merge pull request #8042 from sbueringer/pr-envtest-envvar-kubeconfig

🌱 envtest: add env var to allow writing envtest kubeconfig

Author: k8s-ci-robot

docs/book/src/developer/testing.md

@@ -107,6 +107,10 @@ When running individual tests, it could happen that a testenv is started if this
 However, if the tests you are running don't require testenv (i.e. they are only using fake client), you can skip the testenv
 creation by setting the environment variable `CAPI_DISABLE_TEST_ENV` (to any non-empty value).
 
+To debug testenv unit tests it is possible to use:
+* `CAPI_TEST_ENV_KUBECONFIG` to write out a kubeconfig for the testenv to a file location.
+* `CAPI_TEST_ENV_SKIP_STOP` to skip stopping the testenv after test execution.
+
 </aside>
 
 ## End-to-end tests

internal/test/envtest/environment.go

@@ -103,11 +103,15 @@ type RunInput struct {
 //	because our tests require access to the *Environment. We use this field to make the created Environment available
 //	to the consumer.
 //
-// Note: Test environment creation can be skipped by setting the environment variable `CAPI_DISABLE_TEST_ENV`. This only
-//
-//	makes sense when executing tests which don't require the test environment, e.g. tests using only the fake client.
+// Note: Test environment creation can be skipped by setting the environment variable `CAPI_DISABLE_TEST_ENV`
+// to a non-empty value. This only makes sense when executing tests which don't require the test environment,
+// e.g. tests using only the fake client.
+// Note: It's possible to write a kubeconfig for the test environment to a file by setting `CAPI_TEST_ENV_KUBECONFIG`.
+// Note: It's possible to skip stopping the test env after the tests have been run by setting `CAPI_TEST_ENV_SKIP_STOP`
+// to a non-empty value.
 func Run(ctx context.Context, input RunInput) int {
 	if os.Getenv("CAPI_DISABLE_TEST_ENV") != "" {
+		klog.Info("Skipping test env start as CAPI_DISABLE_TEST_ENV is set")
 		return input.M.Run()
 	}
 
@@ -124,6 +128,16 @@ func Run(ctx context.Context, input RunInput) int {
 	// Start the environment.
 	env.start(ctx)
 
+	if kubeconfigPath := os.Getenv("CAPI_TEST_ENV_KUBECONFIG"); kubeconfigPath != "" {
+		klog.Infof("Writing test env kubeconfig to %q", kubeconfigPath)
+		config := kubeconfig.FromEnvTestConfig(env.Config, &clusterv1.Cluster{
+			ObjectMeta: metav1.ObjectMeta{Name: "test"},
+		})
+		if err := os.WriteFile(kubeconfigPath, config, 0600); err != nil {
+			panic(errors.Wrapf(err, "failed to write the test env kubeconfig"))
+		}
+	}
+
 	if input.MinK8sVersion != "" {
 		if err := version.CheckKubernetesVersion(env.Config, input.MinK8sVersion); err != nil {
 			fmt.Printf("[IMPORTANT] skipping tests after failing version check: %v\n", err)
@@ -140,6 +154,11 @@ func Run(ctx context.Context, input RunInput) int {
 	// Run tests
 	code := input.M.Run()
 
+	if skipStop := os.Getenv("CAPI_TEST_ENV_SKIP_STOP"); skipStop != "" {
+		klog.Info("Skipping test env stop as CAPI_TEST_ENV_SKIP_STOP is set")
+		return code
+	}
+
 	// Tearing down the test environment
 	if err := env.stop(); err != nil {
 		panic(fmt.Sprintf("Failed to stop the test environment: %v", err))