Best way to test exceptions with Assert to ensure they will be thrown

Question

Do you think that this is a good way for testing exceptions? Any suggestions?

Exception exception = null;
try{
    //I m sure that an exeption will happen he         


        

Answer 1

Unfortunately MSTest STILL only really has the ExpectedException attribute (just shows how much MS cares about MSTest) which IMO is pretty awful because it breaks the Arrange/Act/Assert pattern and it doesnt allow you to specify exactly which line of code you expect the exception to occur on.

When I'm using (/forced by a client) to use MSTest I always use this helper class:

public static class AssertException
{
    public static void Throws(Action action) where TException : Exception
    {
        try
        {
            action();
        }
        catch (Exception ex)
        {
            Assert.IsTrue(ex.GetType() == typeof(TException), "Expected exception of type " + typeof(TException) + " but type of " + ex.GetType() + " was thrown instead.");
            return;
        }
        Assert.Fail("Expected exception of type " + typeof(TException) + " but no exception was thrown.");
    }

    public static void Throws(Action action, string expectedMessage) where TException : Exception
    {
        try
        {
            action();
        }
        catch (Exception ex)
        {
            Assert.IsTrue(ex.GetType() == typeof(TException), "Expected exception of type " + typeof(TException) + " but type of " + ex.GetType() + " was thrown instead.");
            Assert.AreEqual(expectedMessage, ex.Message, "Expected exception with a message of '" + expectedMessage + "' but exception with message of '" + ex.Message + "' was thrown instead.");
            return;
        }
        Assert.Fail("Expected exception of type " + typeof(TException) + " but no exception was thrown.");
    }
}

Example of usage:

AssertException.Throws(() => classUnderTest.GetCustomer(null));