I have a couple of projects that get tested on Travis-CI and I just discovered Coveralls, a tool which integrates with it to provide a code coverage badge to go alongside your build status badge. (and is also free for open-source projects)
Unfortunately, it seems that there’s a bug in the current Python client that causes it to error out when submitting coverage data from PyPy builds. (It tries to grab source for compiled PyPy modules with no source available and then dies when it can’t).
Here’s the boilerplate I use to skip it on Python 2.5 (which it doesn’t support), make it complete successfully on PyPy, and omit things like the unit test framework itself from the report: