Log failed tests
Mocha has awful diffs:

How am I supposed to know that problem is with a whitespace?
I'd love to have two separate log files with failed tests: actual.txt and expected.txt, so they can be used with any diff app.
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it's known issue for mocha https://github.com/visionmedia/mocha/pull/710
I think i can implement actual for failed tests. but i think expected is unnecessary because you can always see what's expected in tests sourcecode.
i think in near future many of tests will be implemented like this one https://github.com/csscomb/csscomb.js/blob/master/test/vendor-prefix-align.js
I think mocha (as we use it) is annoying, because it makes me scroll all the time.
We have a long-long cat list of passed tests and if I run npm test 6 times in a row, my console becomes cluttered with unwanted messages and it becomes almost impossible to search through command history.
I need to be precise enough in order to not scroll further than needed or I will accidentally look at output of a previous test run and become stuck trying to figure out why I get the same result again.
Mocha is great as it allows you to write neat and simple code.
And spec is great as it shows you this huge list of passed tests and you feel like a hero.
But every time I need to run tests, I change spec to dot, collect output in 2 files and use Kaleidoscope as a diff tool.
It saves my time a lot, especially when dealing with whitespaces.
Btw, I also vote to change the reporter to something more compact, like dot or nyan, for example. But the diff is still would be bad with whitespaces :(
