Refactor a bunch of common code in yapf_test
Refactor a bunch of common code in yapf_test

thurday/yapf,nikolamilosevic86/yapf,sbc100/yapf,jamesblunt/yapf,elviswf/yapf,wklken/yapf,lucius-feng/yapf,dmoliveira/yapf,sbc100/yapf,hayd/yapf,bygloam/yapf,google/yapf,google/yapf,ambv/yapf,abduld/yapf