Add simple subsurface test case
Add simple subsurface test case

CTPUG/pygame_cffi,GertBurger/pygame_cffi,CTPUG/pygame_cffi,caseyc37/pygame_cffi,GertBurger/pygame_cffi,CTPUG/pygame_cffi,GertBurger/pygame_cffi,caseyc37/pygame_cffi,GertBurger/pygame_cffi,caseyc37/pygame_cffi