It's already happened to me a couple times this week where I'll have a skipped test somewhere and forget to unskip it because when we have skipped tests in our suites it shows all green in the output. I'm sure I'm not the only one this happens to ;)
I propose that when we have skipped tests in our suite, we get the same kind of output that RSpec uses - a yellow asterisk instead of a green dot for that that test. We could also change the color of the summary line at the end, so instead of it being all green, the section at the end that says "1 skipped" would be yellow. It would be kind of like this:
<green>.......................................................................................</green><yellow>*</yellow><green>......................................................................................................................................................................................................................</green>
<green>103 doctests, 198 tests, 0 failures,</green><yellow> 1 skipped</yellow>
I think this would be a really helpful visual cue for users to let them know there's still something that might deserve their attention.
We could also improve the output of `mix test --trace` by highlighting the skipped tests in yellow, which would be consistent. At the moment they have no highlighting, which is the same as the test module names, while passing tests are highlighted in green.