code: public static void awaitReceivedResponses(final SipCall call, final int count) {
      await().until(new Callable<Integer>() {
  
        @Override
        public Integer call() throws Exception {
          return call.getAllReceivedResponses().size();
        }
      }, is(count));
    }
docs: Await until a the size of {@link SipCall#getAllReceivedResponses()} is equal to count.
  
  @param call the {@link SipCall} under test
  @param count the expected amount of responses
  @throws ConditionTimeoutException If condition was not fulfilled within the default time
  period.