fixes nil ptr panic bug (#207)

Co-authored-by: Andreas Neumann <aneumann@mesosphere.com>
Signed-off-by: Ken Sipe <kensipe@gmail.com>

pkg/test/utils/kubernetes.go

@@ -102,12 +102,26 @@ func Retry(ctx context.Context, fn func(context.Context) error, errValidationFun
 	errCh := make(chan error)
 	doneCh := make(chan struct{})
 
+	if fn == nil {
+		log.Println("retry func is nil and will be ignored")
+		return nil
+	}
+
 	// do { } while (err != nil): https://stackoverflow.com/a/32844744/10892393
 	for ok := true; ok; ok = lastErr != nil {
 		// run the function in a goroutine and close it once it is finished so that
 		// we can use select to wait for both the function return and the context deadline.
 
 		go func() {
+			// if the func we are calling panics, clean up and call it done
+			// the common case is when a shared reference, like a client, is nil and is called in the function
+			defer func() {
+				if r := recover(); r != nil {
+					//log.Println("retry func has panicked and will be ignored")
+					errCh <- errors.New("func passed to retry panicked.  expected if testsuite is shutting down")
+				}
+			}()
+
 			if err := fn(ctx); err != nil {
 				errCh <- err
 			} else {

pkg/test/utils/kubernetes_test.go

@@ -118,6 +118,24 @@ func TestRetryWithUnexpectedError(t *testing.T) {
 	assert.Equal(t, 1, index)
 }
 
+func TestRetryWithNil(t *testing.T) {
+	assert.Equal(t, nil, Retry(context.TODO(), nil, IsJSONSyntaxError))
+}
+
+func TestRetryWithNilFromFn(t *testing.T) {
+	assert.Equal(t, nil, Retry(context.TODO(), func(ctx context.Context) error {
+		return nil
+	}, IsJSONSyntaxError))
+}
+
+func TestRetryWithNilInFn(t *testing.T) {
+	client := RetryClient{}
+	var list runtime.Object
+	assert.Error(t, Retry(context.TODO(), func(ctx context.Context) error {
+		return client.Client.List(ctx, list)
+	}, IsJSONSyntaxError))
+}
+
 func TestRetryWithTimeout(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
 	defer cancel()