rank_filter.recipe/run_test.py: Switch to using `unittest` directly.
rank_filter.recipe/run_test.py: Switch to using `unittest` directly.

jakirkham/rank_filter,jakirkham/rank_filter,nanshe-org/rank_filter,DudLab/rank_filter,DudLab/rank_filter,nanshe-org/rank_filter,nanshe-org/rank_filter,DudLab/rank_filter,jakirkham/rank_filter