Cool article. What about hiding the test code to the students to make sure they don't write their solutions specifically to make their tests pass? Maybe using a git submodule or something?<p>Besides, I'd be curious to read about your app that runs the tests by itself. Are you going to open-source it? Because until now, I only found paying solutions to having a platform running my tests before I deploy, when I'm pretty sure an Heroku app could handle that pretty well...