Fix a race detector error in a unit test

Signed-off-by: Ryan Richard <richardry@vmware.com>

internal/controller/impersonatorconfig/impersonator_config.go

@@ -357,7 +357,7 @@ func (c *impersonatorConfigController) ensureImpersonatorIsStarted(syncCtx contr
 			// The server has stopped, so finish shutting it down.
 			// If that fails too, return both errors for logging purposes.
 			// By returning an error, the sync function will be called again
-			// and we'll have a change to restart the server.
+			// and we'll have a chance to restart the server.
 			close(c.errorCh) // We don't want ensureImpersonatorIsStopped to block on reading this channel.
 			stoppingErr := c.ensureImpersonatorIsStopped(false)
 			return errors.NewAggregate([]error{runningErr, stoppingErr})

internal/controller/impersonatorconfig/impersonator_config_test.go

@@ -289,14 +289,15 @@ func TestImpersonatorConfigControllerSync(t *testing.T) {
 		var cancelContext context.Context
 		var cancelContextCancelFunc context.CancelFunc
 		var syncContext *controllerlib.Context
-		var impersonatorFuncWasCalled int
-		var impersonatorFuncError error
-		var impersonatorFuncReturnedFuncError error
-		var startedTLSListener net.Listener
 		var frozenNow time.Time
 		var signingCertProvider dynamiccert.Provider
 		var signingCACertPEM, signingCAKeyPEM []byte
 		var signingCASecret *corev1.Secret
+		var impersonatorFuncWasCalled int
+		var impersonatorFuncError error
+		var impersonatorFuncReturnedFuncError error
+		var startedTLSListener net.Listener
+		var startedTLSListenerMutex sync.RWMutex
 		var testHTTPServer *http.Server
 		var testHTTPServerMutex sync.RWMutex
 		var testHTTPServerInterruptCh chan struct{}
@@ -317,17 +318,10 @@ func TestImpersonatorConfigControllerSync(t *testing.T) {
 				return nil, impersonatorFuncError
 			}
 
-			// Return a func that starts a fake server when called, and shuts down the fake server when stopCh is closed.
+			startedTLSListenerMutex.Lock() // this is to satisfy the race detector
-			// This fake server is enough like the real impersonation proxy server for this unit test because it
+			defer startedTLSListenerMutex.Unlock()
-			// uses the supplied providers to serve TLS. The goal of this unit test is to make sure that the server
-			// was started/stopped/configured correctly, not to test the actual impersonation behavior.
-			return func(stopCh <-chan struct{}) error {
-				if impersonatorFuncReturnedFuncError != nil {
-					return impersonatorFuncReturnedFuncError
-				}
-
 			var err error
-				// automatically choose the port for unit tests
+			// Bind a listener to the port. Automatically choose the port for unit tests instead of using the real port.
 			startedTLSListener, err = tls.Listen("tcp", localhostIP+":0", &tls.Config{
 				MinVersion: tls.VersionTLS12,
 				GetCertificate: func(info *tls.ClientHelloInfo) (*tls.Certificate, error) {
@@ -344,7 +338,7 @@ func TestImpersonatorConfigControllerSync(t *testing.T) {
 					// Docs say that this will always be called in tls.RequestClientCert mode
 					// and that the second parameter will always be nil in that case.
 					// rawCerts will be raw ASN.1 certificates provided by the peer.
-						if rawCerts == nil || len(rawCerts) != 1 {
+					if len(rawCerts) != 1 {
 						return fmt.Errorf("expected to get one client cert on incoming request to test server")
 					}
 					clientCert := rawCerts[0]
@@ -356,7 +350,6 @@ func TestImpersonatorConfigControllerSync(t *testing.T) {
 					// the CAContentProvider that was passed in.
 					parsed, err := x509.ParseCertificate(clientCert)
 					require.NoError(t, err)
-						t.Log("PARSED CLIENT CERT")
 					roots := x509.NewCertPool()
 					require.True(t, roots.AppendCertsFromPEM(currentClientCertCA))
 					opts := x509.VerifyOptions{Roots: roots}
@@ -367,6 +360,15 @@ func TestImpersonatorConfigControllerSync(t *testing.T) {
 			})
 			r.NoError(err)
 
+			// Return a func that starts a fake server when called, and shuts down the fake server when stopCh is closed.
+			// This fake server is enough like the real impersonation proxy server for this unit test because it
+			// uses the supplied providers to serve TLS. The goal of this unit test is to make sure that the server
+			// was started/stopped/configured correctly, not to test the actual impersonation behavior.
+			return func(stopCh <-chan struct{}) error {
+				if impersonatorFuncReturnedFuncError != nil {
+					return impersonatorFuncReturnedFuncError
+				}
+
 				testHTTPServerMutex.Lock() // this is to satisfy the race detector
 				testHTTPServer = &http.Server{Handler: http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
 					_, err := fmt.Fprint(w, fakeServerResponseBody)
@@ -376,7 +378,10 @@ func TestImpersonatorConfigControllerSync(t *testing.T) {
 
 				// Start serving requests in the background.
 				go func() {
-					err := testHTTPServer.Serve(startedTLSListener)
+					startedTLSListenerMutex.RLock() // this is to satisfy the race detector
+					listener := startedTLSListener
+					startedTLSListenerMutex.RUnlock()
+					err := testHTTPServer.Serve(listener)
 					if !errors.Is(err, http.ErrServerClosed) {
 						t.Log("Got an unexpected error while starting the fake http server!")
 						r.NoError(err) // causes the test to crash, which is good enough because this should never happen
@@ -394,7 +399,7 @@ func TestImpersonatorConfigControllerSync(t *testing.T) {
 					<-testHTTPServerInterruptCh
 				}
 
-				err = testHTTPServer.Close()
+				err := testHTTPServer.Close()
 				t.Log("Got an unexpected error while stopping the fake http server!")
 				r.NoError(err) // causes the test to crash, which is good enough because this should never happen
 
@@ -403,11 +408,15 @@ func TestImpersonatorConfigControllerSync(t *testing.T) {
 		}
 
 		var testServerAddr = func() string {
+			var listener net.Listener
 			require.Eventually(t, func() bool {
-				return startedTLSListener != nil
+				startedTLSListenerMutex.RLock() // this is to satisfy the race detector
+				listener = startedTLSListener
+				defer startedTLSListenerMutex.RUnlock()
+				return listener != nil
 			}, 20*time.Second, 50*time.Millisecond, "TLS listener never became not nil")
 
-			return startedTLSListener.Addr().String()
+			return listener.Addr().String()
 		}
 
 		var closeTestHTTPServer = func() {
@@ -1967,9 +1976,15 @@ func TestImpersonatorConfigControllerSync(t *testing.T) {
 				startInformersAndController()
 				// The failure happens in a background goroutine, so the first sync succeeds.
 				r.NoError(runControllerSync())
-				// Eventually the server is not really running, because the startup failed.
+				// The imperonatorFunc was called to construct an impersonator.
-				r.Nil(startedTLSListener)
 				r.Equal(impersonatorFuncWasCalled, 1)
+				// Without waiting too long because we don't want the test to be slow, check if it seems like the
+				// server never started.
+				r.Never(func() bool {
+					testHTTPServerMutex.RLock() // this is to satisfy the race detector
+					defer testHTTPServerMutex.RUnlock()
+					return testHTTPServer != nil
+				}, 2*time.Second, 50*time.Millisecond)
 				r.Len(kubeAPIClient.Actions(), 3)
 				requireNodesListed(kubeAPIClient.Actions()[0])
 				requireLoadBalancerWasCreated(kubeAPIClient.Actions()[1])