Fix patching of the test framework's 'it' function in test suites spanning multiple files

[papandreou]

As reported by @alexjeffburke and discussed on the gitter channel.

The fix should only affect multi-file mocha suites, and I've tested that the test framework patch still does the correct thing with make test-jasmine, and make test-browser in Chrome.

[papandreou]

We can't really do much about the coverage level, except for adding a separate (and probably very volatile) mock environment for testing it.

[sunesimonsen]

LGTM

[alexjeffburke]

Hi, I've been away for the last couple of days so can't yet check this. But my quick 2 øre: I know this is a little dirty and it's probably a tricky thing to maintain, but it is very useful. So if the result with patch is as simple as you get an exception that something is likely missing from your test (i.e. that blasted return) it's fantastic because it is SO easy to do. Will give master a go next chance I get. AJB

[papandreou]

@alexjeffburke It's out in 9.5.2 now.

[alexjeffburke]

The fix here has worked great - you now receive "Error: When using asynchronous assertions you must return a promise from the it block". Clearly indicates something is missing, and by the time you've fixed that you'll be back to dealing with the result of your actual test cases. Footgun disarmed :)