Add basic error case test support

[bitwiseman]

I'd work on #270, but in order to do so and know if I fixed it I needed to have the build support checking behavior in expected error cases.

Turned on timeout tests as proof of concept.

[bitwiseman]

@visionmedia Can we merge this in, please?
It is a test-only change that open the door for testing of failure and error cases. Coverage in these scenarios is vital to the stability and reliablity of the product. I'm surprised no one has done this yet.

[bitwiseman]

@visionmedia said:

I'm all down for failure tests but I'd definitely prefer to use node so we have some more flexibility with the assertions.

Hmm... The problem is that we need to cover cases where there are uncaught exceptions. I guess I can go back to and write this in javascript, but really we don't want that - we want to know what happens when we call mocha from the command line.

[bitwiseman]

@visionmedia - Ping?

[bitwiseman]

@visionmedia - Any feedback? Do I need to reimplement in javascript?

[tj]

well you can still use javascript to test exec()s that use the shell so it would be the same, just easier to keep platform / shell independent

[bitwiseman]

Cool, will do.

[tj]

closing for now just to clean up the queue a bit