    def test_wrapper(self):
        """
        Check that you can create a blank Screen.
        """
        def internal_checks(screen):
            # Check screen basically exists
            self.assertIsNotNone(screen)
            self.assertGreater(screen.width, 0)
            self.assertGreater(screen.height, 0)
            self.assertGreater(screen.colours, 0)

            # Check that the Screen is cleared ready for use.
            for x in range(screen.width):
                for y in range(screen.height):
                    char, fg, attr, bg = screen.get_from(x, y)
                    self.assertEqual(char, ord(" "))
                    self.assertEqual(fg, Screen.COLOUR_WHITE)
                    self.assertEqual(attr, 0)
                    self.assertEqual(bg, Screen.COLOUR_BLACK)

        Screen.wrapper(internal_checks)
Check that you can create a blank Screen.
tests/test_screen.py