We've just gotten the testing environment working with the Git migration, see http://qa.scratch.drupal.org.
When you test on git-dev, could you please post patches and note the result? Please post working patches and broken patches. re-test patches. D7 core and D6/7 contrib (on projects that have testing turned on). Keep notes and make sure the results are what you expect.
Edit: Heard talk of switching to a different style of patches? Probably will happen. But right now, we're talking about regular patch -p0 traditional patches like in http://drupal.org/patch.
Edit:The patch format for the future has been changed to the more normal patch -p1. The Patch Contributor Guide has explanations of how to roll a patch using git format-patch.
Another Edit: I have tried to make the testbot forgiving of -p0 patches, so patches that are already in the queue should test as they did on the old system. Please use -p1 for new patches, but I'm hoping that the compromise @berdir proposed and I implemented will work for both.
I should have made this a wiki, but don't know how to change it at this point. However, I have a testbot testplan that all of you can edit. I would appreciate it if you'd go through it rigorously for your project and note the results.
Thanks,
-Randy

Comments
How do you turn on pifr
How do you turn on pifr testing for projects? (Just curious)
I go by Josh The Geek.
Drupal.org
GitHub
There is an issue in Infrastructure queue
Sign up your contrib project that has tests at http://drupal.org/node/689990.