def test_mazeprops4(self):
     mc = MazeClause([])
     self.assertFalse(mc.is_valid())
     self.assertTrue(mc.is_empty())
 def test_mazeprops3(self):
     mc = MazeClause([(("X", (1, 1)), True), (("Y", (2, 1)), True), (("X", (1, 1)), False)])
     self.assertTrue(mc.is_valid())
     self.assertTrue(mc.get_prop(("X", (1, 1))) is None)
     self.assertFalse(mc.is_empty())