code: public static void assertResponseReceived(String msg, int statusCode, MessageListener obj) {
      assertNotNull("Null assert object passed in", obj);
      assertTrue(msg, responseReceived(statusCode, obj));
    }
docs: Asserts that the given message listener object received a response with the indicated status
  code. Assertion failure output includes the given message text.
  
  @param msg message text to output if the assertion fails.
  @param statusCode The response status code to check for (eg, SipResponse.RINGING)
  @param obj The MessageListener object (ie, SipCall, Subscription, etc.).