Here is what I see using recipes.py test train with filtre.

/usr/local/google/code/infra/build/scripts/slave$ ./recipes.py test train --filter XXXXXXXXXXXXXXXXXYYYYYYYYYYYYYYYYYYZZZZZZZZZZZZZZZZZZZ

NOTE: not checking coverage, because a filter is enabled
NOTE: not checking for unused expectations, because a filter is enabled
----------------------------------------------------------------------
Ran 0 tests in 0.912s

OK
Generating README.recipes.md

Is this intended behavior?