To make a new buildbot test case, create a new directory called bulidbot_test_{testname}, then put a "runme" and a "buildbot_runtest.sh" inside. The runme should intelligently change targets depending on what machine it's running on (see buildbot_test_leakcheck/runme for an example). The exit code of buildbot_runtest.sh should be 0 on success, !0 on failure. Buildbot tests are run when changes are pushed to the testing branch on fishercat:/srv/git/openggcm.git.
