But from English it not sounds like it should be occurred in past. So what correct and not long sentence can be used here? maybe:mock had received someMessagemock should haveReceived someMessage
And same question for verification group of message sends (at the end of test):[mock someMessage. mock2 someMessage2] should occur[mock someMessage. mock2 someMessage2] should occurInSameOrder[ mock someMessage. mock2 somMessage2 ] should have beenSent