I recently upgraded my Force.com IDE (and all projects) to the Winter '12 release. Since upgrading, I've been observing that when I attempt to run unit tests against an Apex class, it often takes a very long time to execute. Even relatively simple tests sometimes take a minute or two to complete. The time doesn't seem to be spent during test execution, but rather during the "preparing results..." phase (based on the progress indicator in the IDE). Reducing the log level doesn't seem to have any impact one way or the other. I've also seen it simply get stuck in the "preparing results..." phase to the point where I had to kill the Eclipse process. Anyone else seeing this?