#NEWLINE# @ contextmanager #NEWLINE# def assert_creates_file( self , path ) : #NEWLINE# #INDENT# self . assert_true ( ( not os . path . exists ( path ) ) , '{} should not exist' . format ( path ) ) #NEWLINE# ( yield ) #NEWLINE# self . assert_true ( os . path . exists ( self ) , '{} should exist' . format ( path ) )