Mocking SendMail Workflow Activity

[Steve]

Hi folks, I am trying to mock the SendMail windows workflow activity.

In this default workflow, the SmtpClient calls SendAsync(), and without a callback, the workflow just hangs forever.  So obviously, i need to fake out SendAsync() so that no email is sent, but I also want to 'DoInstead' and trigger the SendComplete event.  Am I missing anything obvious in my code snippet below?


        public UnitTestProject()
        {
        Mock.Replace<SmtpClient>(x => x.SendAsync(Arg.IsAny<MailMessage>(), null)).In<SendMail>();    
        }


        [TestMethod]
        public void TestSendMail()
        {   
            var smtpClient = new SmtpClient(Arg.AnyString);            
            var args = new System.ComponentModel.AsyncCompletedEventArgs(null, false, null);
                        
            Mock.Arrange(() => smtpClient.SendAsync(Arg.IsAny<MailMessage>(), null))
                        .IgnoreArguments()
                        .IgnoreInstance()
                        .DoInstead(
                        () => Mock.Raise(
                                () => smtpClient.SendCompleted += null, args)
                        );   // not raising the event ...
       
                                                  
            var wit = new WorkflowInvokerTest(new SendMail
            {
                Body = "BodyString",
                IsBodyHtml = true,
                CC = "[e-mail]",
                To = "[e-mail]",
                From = "[e-mail]",
                Sender = "[e-mail]",
                Subject = "Unit testing"
            });            
                        
            wit.TestActivity();
            Mock.Assert(smtpClient);
        }       

        

[Steve]

Once I made the event public, I was able to mock it out as follows:


 Mock.Arrange(() => smtpClient.SendAsync(Arg.IsAny<MailMessage>(), null))
                     .IgnoreArguments()
                     .IgnoreInstance()
                     .DoInstead(() => sm.smtpClient_SendCompleted(null, args))
                     .OccursOnce();    

[Steve]

Eh, I don't want to break encapsulation to unit test this activity.

Can you help me figure out why this throws a generic exception saying "Can't mock the expected event."

Mock.Arrange(() => smtpClient.SendAsync(Arg.IsAny<MailMessage>(), null))
                     .IgnoreArguments()
                     .IgnoreInstance()
                     .Raises( () => smtpClient.SendCompleted += null, args)
                     .OccursOnce();  

[Steve]

My problem is related to raising events, so I created a more accurate thread here:

http://www.telerik.com/community/forums/justmock/general-discussions/cannot-raise-events.aspx


You can close/delete this thread.

[Kaloyan]

Hi Steven,

I apologize for the late reply.

However, investigating your examples, I noticed that you will need to create a concrete mock to hold the certain arrange. Please check the following example, which is the same as yours with the only difference that "smtpClient" is a mock of the original "SmtpClient" class:

[TestMethod]

public void ShouldRaiseAnEventOnSendAsyncInvocation()

{

    var smtpClient = Mock.Create<SmtpClient>(Behavior.CallOriginal);           

    var args = new System.ComponentModel.AsyncCompletedEventArgs(null, false, null);

             

    Mock.Arrange(() => smtpClient.SendAsync(Arg.IsAny<MailMessage>(), null))

        .IgnoreArguments()

        .IgnoreInstance()

        .DoInstead(

        () => Mock.Raise(

            () => smtpClient.SendCompleted += null, args)); 


 

    smtpClient.SendAsync(new MailMessage(),null);

}

You could see that the above example does not throw the "Can't mock the expected event." exception and it behaves as expected.

To help you further, I must note that the "Mock.Replace" should be only used when your goal is to fake MsCorlib members, for everything else you should be using Mock.Create<T>(). You could read more about mocking MsCorlib members, here.

I hope this helps.

All the best,
Kaloyan
the Telerik team