NUnit - ExpectedMessage differs error

Question

I am quite new to TDD and am going with NUnit and Moq. I have got a method where I expect an exception, so I wanted to play a little with the frameworks features.

My test code looks as follows:

    [Test]
    [ExpectedException(ExpectedException = typeof(MockException), ExpectedMessage = "Actual differs from expected")]
    public void Write_MessageLogWithCategoryInfoFail()
    {
        string message = "Info Test Message";

        Write_MessageLogWithCategory(message, "Info");

        _LogTest.Verify(writeMessage =>
            writeMessage.Info("This should fail"),
            "Actual differs from expected"
        );
    }

But I always receive the errormessage that the error message that the actual exception message differs from the expected message. What am I doing wrong?

Hopping that I understood you correctly, I'm using NUnit version 2.5.1 — Mark, Jun 09 '10 at 13:15
and you are running your tests using nunit-gui.exe? Or you are running them from Visual Studio in some way? — Grzenio, Jun 09 '10 at 14:01

score 3 · Accepted Answer · answered Jun 09 '10 at 14:43

3

Unfortunately Resharper test runner has a bug/limitation - it doesn't handle the ExpectedException attributes. You have 2 options:

Use some other test runner (e.g. nunit-gui.exe, shipped with NUnit) - but this approach makes it a pain to debug your tests

Catch and validate the exception manually, using the following pattern:

[Test] public void Write_MessageLogWithCategoryInfoFail() { try { string message = "Info Test Message";

  Write_MessageLogWithCategory(message, "Info");

  _LogTest.Verify(writeMessage =>
      writeMessage.Info("This should fail"),
      "Actual differs from expected"
  );
  Assert.Fail("Expected exception");
}
catch(MockException e)
{
  Assert.AreEqual("Actual differs from expected", e.Message);
}

}

Its a real shame, because the descriptive way of saying that you expect an exception is much nicer!

On a side note I hope that the code above is only for playing with the framework - usually you would never catch MockExceptions :)

answered Jun 09 '10 at 14:43

Grzenio

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Thanks I tested your code and I think I know now why it never was equal. The message in the exception is larger due to a more detailed error message: "Actual differs from expected\r\nInvocation was not performed on the mock: writeMessage => writeMessage.Info(\"This should fail\")" But thanks for the hint! And even though this test runs over production code.. Yes I'm playing around with framework ;-) – Mark Jun 09 '10 at 15:05
I got a similar error running an NUnit test with TestDrivet.Net: The exception message text was incorrect Expected: Password_too_short but was: Password_too_short EDIT: in my case the message was really different (continued after a line break) – Cristian Lupascu Aug 23 '11 at 08:16
@w0lf, you mean that there was a line break at the end of the exception message, but not in what you passed in TestDriven.NET? – Jennifer S Feb 07 '12 at 17:07
@JenniferS Yes. I somehow saw the messages side-by-side in the NUnit output and they seemed equal. But then I figured it out... – Cristian Lupascu Feb 07 '12 at 17:27
The ReSharper Test runner as of today handles the attributes. I have version JetBrains ReSharper 7.1.3 C# Edition Build 7.1.3000.2254 using Visual Studio 2010 (Version 10.0.40219.1) – Marcel Dec 27 '13 at 14:49
@Grzenio Please consider my comment about ReSharper – Marcel Dec 27 '13 at 14:57
@Marcel, they must have fixed it at last! – Grzenio Dec 30 '13 at 09:39

score 2 · Answer 2 · edited Jul 15 '12 at 19:46

2

You may use the extra parameter MatchType = MessageMatch.Regex.

edited Jul 15 '12 at 19:46

Rob Hruska

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answered Jul 15 '12 at 18:41

Chris

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think about providing additional explanation why do you think this will fix the issue. Also more details on how to apply your solution, probably a code snippet would be the best idea. – George Mamaladze Jul 15 '12 at 19:05
When using Resharper this doesn't help the problem. – Nathan C. Tresch Mar 18 '15 at 20:03

NUnit - ExpectedMessage differs error

2 Answers2