def test_garbage_collection(self):
"""check garbage collection for Python defined Attributes
"""
# check if attributes are garbage collected
pq = PairQuantity()
wpq = weakref.ref(pq)
self.assertFalse(wpq() is None)
pq._registerDoubleAttribute('foo')
pq.foo = 45
self.assertEqual(45, pq._getDoubleAttr('foo'))
del pq
self.assertTrue(wpq() is None)
return