drothlis/stb-tester — pull request #240 by wmanley (2014-12-17 18:50:38+00:00)
Title: API: `is_screen_black`: Make `frame` parameter optional

This makes it consistent with the other functions such as `match()`, and makes it more useful with a hypothetical `wait_until`, allowing constructions such as:

assert wait_until(is_screen_black)