Explicitly setting a test to pass/fail?

Question

In the test below, if it enters the catch block I want to indicate that the test has passed. If the catch block is bypassed I want the test to fail.

Is there a way to do this, or am I missing the point with how tests should be structured?

[TestMethod]
public void CommandExecutionWillThrowExceptionIfUserDoesNotHaveEnoughEminence()
{
    IUserCommand cmd = CreateDummyCommand("TEST", 10, 10);
    IUser user = new User("chris", 40);

    try
    {
        cmd.Execute(user);
    }
    catch(UserCannotExecuteCommandException e)
    {
        //Test Passed
    }

    // Test Failed
}

`CommandExecutionWillThrowExceptionIfUserDoesNotHaveEnoughEminence`? — Daniel, Dec 04 '11 at 04:52
http://stackoverflow.com/questions/933613/c-how-do-i-use-assert-unit-testing-to-verify-that-an-exception-has-been-thro — BentOnCoding, Dec 04 '11 at 04:58

score 9 · Answer 1 · answered Dec 04 '11 at 04:48

9

I tend to use this pattern when I have a similar situation:

// ...
catch (UserCannotExecuteCommandException e)
{
    return;    // Test Passed
}

Assert.Fail();    // Test Failed -- expected exception not thrown

answered Dec 04 '11 at 04:48

Cameron

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score 6 · Accepted Answer · answered Dec 04 '11 at 04:49

6

Declare the test to throw UserCannotExecuteCommandException, when that happens the test will succeed

[ExpectedException( typeof( UserCannotExecuteCommandException) )]

answered Dec 04 '11 at 04:49

Orn Kristjansson

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But does the test also succeed if the exception is *not* thrown? The OP needs the test to fail if no exception is thrown. – Cameron Dec 04 '11 at 04:51
Thanks for this. How do I prevent Visual Studio from stopping the execution of the tests when the actual exception is thrown? For example, I have to press F5/Continue before the test continues and can be marked as passed. – Chris Dec 04 '11 at 05:02
2

@Chris: Run the test *without* debugging (CTRL R, T) – Cameron Dec 04 '11 at 05:06

sll · Answer 3 · 2011-12-04T21:06:11.757

1

I would suggest using Assert.Throws() method:

Assert.Throws<UserCannotExecuteCommandException>() => cmd.Execute(user));

Id does all what you need. It expect that an exception of type UserCannotExecuteCommandException would be thrown whilst execution of the cmd.Execute() method, otherwise automatially marks a test as failed.

edited Dec 04 '11 at 21:06

answered Dec 04 '11 at 20:39

sll

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score 0 · Answer 4 · answered Aug 24 '21 at 09:27

Since [ExpectedException(...)] is concidered as a bad practice you might use:

MSTest: Assert.ThrowsException<UserCannotExecuteCommandException >( () => cmd.Execute(user) );
NUnit: Assert.Throws<UserCannotExecuteCommandException >( () => cmd.Execute(user) );

then you are able to point which line exactly should throw an exception.

Explicitly setting a test to pass/fail?

4 Answers4