NCrunchI stumbled upon NCrunch some time ago, a .Net test runner for Visual Studio. This is represents a whole new paradigm when it comes to running tests. Actually the developer does not need to run the tests anymore -- NCrunch does it for you while typing. You don't even need to save the file!
While you edit the code, NCrunch uses coloured dots to the left of the code to indicate the test status of that particular line.
Hopefully your code usually looks like this, with happy green dots covering everything. That means your code is covered by passing tests. Production code is to the left and test code to the right:
|All systems operational|
What if we comment out some tests so that parts of the production code is no longer covered by tests? NCrunch marks the non-covered lines with black dots... and all bets are off!
By the way, I am not affiliated with the authors of NCrunch in any way. I'm just a happy user.