Sublime Text has many features that make it my favorite text editor for Mac. One of them is split view.
Having a test suite on the left and its corresponding source file on the right is so much more efficient for test-driven development than tabbing between tests and source files. This system works especially well when multiple test suites and corresponding source files are involved - tests can go on the left and source files on the right. Xcode also offers this layout through the "Assistant" feature, and Eclipse has it as well.
Now if I only had a way to open the corresponding source file from a test file with a keyboard shortcut.