How to prevent expected exceptions from breaking the debug test run?

Question

When running MSTEST unit tests in debug mode, the execution stops in every expected exception that is thrown. My test looks like this

[TestMethod()]
[ExpectedException(typeof(ArgumentNullException))]
public void ShouldThrowExceptionWhenPassingNull()
{
    object data = null;
    target.CheckNull(data);
}

the target method looks like this:

public void CheckNull(object data)
{
    if (ReferenceEquals(null, data))
    {
        throw new ArgumentNullException("data");
    }
} // test run breaks here: ArgumentNullException was unhandled by user code

Answer 1

Did you try running the tests using ctrl-R ctrl-T instead of ctrl-R T?

EDIT If it's not a keyboard shortcut issue, then check out this link. You could try the following as noted there:

1. Disable "break on user unhandled exceptions" for the exception types you you are encountering here (via Debug -> Exceptions)
2. Disable "break on user unhandled exceptions" for all exceptions (via Debug -> Exceptions)
3. Disable "Just My Code"

Answer 2

CTRL + R A works for me without changing any option.

I think the problem you have is because you are running the test project from the Start Debugging (F5) button on the toolbar. If you click the green play button, you will stop in every exception, even expected ones.

To run all tests without stopping in every exception, click on: Test -> Run -> All Tests in Solution or use the shortcut: CTRL + R, A

With the test results window open, CTRL + R, D also works. In the test results window it becomes clear the difference between Run Tests and Debug tests.

Answer 3

@dcp's suggestion looks like it would work for MSTEST, but you might want to consider getting TestDriven.Net. I use it as a test runner almost exclusively and don't have this problem using the right-click "Run Tests in Debug" mode. In addition I find it to be more convenient than the built-in test runner in almost all circumstances.