    def test_frame_themes(self):
        """
        Check we can set a colour theme for a Frame.
        """
        # Now set up the Frame ready for testing
        screen = MagicMock(spec=Screen, colours=8, unicode_aware=False)
        canvas = Canvas(screen, 10, 40, 0, 0)
        form = Frame(canvas, canvas.height, canvas.width)

        # Check colour changes work...
        self.assertEqual(
            form.palette["background"],
            (Screen.COLOUR_WHITE, Screen.A_NORMAL, Screen.COLOUR_BLUE))
        form.set_theme("monochrome")
        self.assertEqual(
            form.palette["background"],
            (Screen.COLOUR_WHITE, Screen.A_NORMAL, Screen.COLOUR_BLACK))

        # Check that a bad theme name has no effect.
        form.set_theme("blah - this doesn't exist")
        self.assertEqual(
            form.palette["background"],
            (Screen.COLOUR_WHITE, Screen.A_NORMAL, Screen.COLOUR_BLACK))
Check we can set a colour theme for a Frame.
tests/test_widgets.py