public void Test_that_Reject_call_calls_Reject_method_of_underlying_consumer_with_correct_delivery_tag() { const ulong deliveryTag = 42; var consumerMock = new Mock <IMessageConsumer>(); var message = new EnvelopedMessage ( Enumerable.Empty <byte>(), consumerMock.Object, string.Empty, string.Empty, deliveryTag, string.Empty ); message.Reject(); consumerMock.Verify(x => x.Reject(deliveryTag), Times.Once); }