def test_descend_classes_and_funcs():
# create module hierarchy
a = ModuleType('a')
a.b = ModuleType('a.b')
# populate with classes
a.A = type('A', (), {})
a.A.__module__ = a.__name__
a.b.B = type('B', (), {})
a.b.B.__module__ = a.b.__name__
# create a loop to check if that gets caught
a.b.a = a
assert {a.A, a.b.B} == set(descend_classes_and_funcs(a, 'a'))
