fix(tests): simulate start/stop in mock credentials provider

Author: ndyakov

redis_test.go

@@ -874,9 +874,12 @@ func (m *mockStreamingProvider) Subscribe(listener auth.CredentialsListener) (au
 	if m.err != nil {
 		return nil, nil, m.err
 	}
-
-	// Send initial credentials
-	listener.OnNext(m.credentials)
+	select {
+	case <-m.updates:
+		// simulate start/stop
+		m.updates = make(chan auth.Credentials, 1)
+	default:
+	}
 
 	// Start goroutine to handle updates
 	go func() {