Add command to run specific test cases

[Ashton-W]

While editing a test it would be great to be able to run it and only it. Or to specify a test class or file to quickly test.

This will be tricky. If you look at facebooks xctool you will find they do this by creating a temporary scheme.

[gfontenot]

Yeah, this might be out of scope for the current plan. I think the reasonable way to start would be to add more configuration so that users can specify that they would like to use xctool instead of xcodebuild as their build tool. We'd need way more than that to get single test or test class or test file support though. We could look to rspec.vim for inspiration on this.