def test_invalid_index(self):
world = World()
realm0 = world.create_realm('Realm0', 0.1, 0.2, 0.3)
realm1 = world.create_realm('Realm1', 0.1, 0.2, 0.3)
self.assertEqual(None, world.get_realm(-1))
self.assertEqual(None, world.get_realm(2))
self.assertEqual(None, world.get_realm(None))
def test_get_realm(self):
world = World()
realm0 = world.create_realm('Realm0', 0.1, 0.2, 0.3)
realm1 = world.create_realm('Realm1', 0.1, 0.2, 0.3)
self.assertEqual(realm0, world.get_realm(0))
self.assertEqual(realm1, world.get_realm(1))
