def test_custom(self):
config = Config()
config.foo = 'foo'
config.bar = 'bar'
c1 = Configurable(config=config)
c2 = Configurable(config=c1.config)
c3 = Configurable(config=c2.config)
self.assertEqual(c1.config, config)
self.assertEqual(c2.config, config)
self.assertEqual(c3.config, config)
# Test that copies are not made
self.assertTrue(c1.config is config)
self.assertTrue(c2.config is config)
self.assertTrue(c3.config is config)
self.assertTrue(c1.config is c2.config)
self.assertTrue(c2.config is c3.config)
