tests: convert more tests to pytest

Change-Id: Id4d48b61dc435564c336385bbc4944eb475d1942
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/569443
Tested-by: Mike Frysinger <vapier@google.com>
Commit-Queue: Mike Frysinger <vapier@google.com>
Reviewed-by: Gavin Mak <gavinmak@google.com>

Author: vapier