MXUnit allows an annotation on a test method. TestBox doesn't appear to pay attention to this.
We have this already, so not sure why it is not working for you, can you verify below please.
Also in our test suites:
Odd. I'll test when I get home, on a clean environment.
I cannot create a repro case for this @ the moment. I'll get back to you, but I'd say park this for the time being.
I can confirm the code in Luis's comment above does work when running inside an MXUnit test. I did notice that the second example does fail if I remove the message from the throw(). I assume this is related to Sean C's bug regarding the empty message not being matched.