public void When_publishing_with_user_defined_message_id_should_set_defined_id_and_header() { const string expectedMessageID = "expected message id"; var publishPipeline = new FakePipeline <IOutgoingPublishContext>(); var context = CreateContext(publishPipeline); var publishOptions = new PublishOptions(); publishOptions.SetMessageId(expectedMessageID); MessageOperations.Publish <MyMessage>(context, m => { }, publishOptions); Assert.AreEqual(expectedMessageID, publishPipeline.ReceivedContext.MessageId); Assert.AreEqual(expectedMessageID, publishPipeline.ReceivedContext.Headers[Headers.MessageId]); }