    def test_refresh(self):
        """
        Check that refresh works.
        """
        def internal_checks(screen):
            # Not much we can do here as refresh will draw to a screen we can't
            # query. Check that we don't hit an Exception on refresh().
            screen.print_at("Hello world!",
                            0, 0,
                            colour=Screen.COLOUR_CYAN,
                            attr=Screen.A_BOLD,
                            bg=Screen.COLOUR_BLUE)
            screen.refresh()

        Screen.wrapper(
            check_screen_and_canvas, height=15, arguments=[internal_checks])
Check that refresh works.
tests/test_screen.py