You did say teammates right?
Right. And I don't expect to have to do this for more than another week.
If you're on a project where people are checking in stuff that doesn't work, or only, uh, partially works, there are a couple of ways to handle it. You could quietly fix stuff yourself, but then they won't learn (and they'd probably get pissed at you for reaching into their code). Or you can mark up a listing and hand it to them. Or you can say, without pointing out any specific fault, "I don't care how you implement this, but we've agreed on the interface, and I'm going to hold you to that agreement." A unit test does the latter, and shifts the pain, if any, where it belongs. And if others on the team need to do this to me, then I deserve it.
Standing up for your agreements early in a project can save you a lot of work later on.