'Make sure we can detect potential circular dependencies in
parent/child relationships.'

@pytest.mark.move
def test_circular_dependency(self):

    parent = document(title='Parent    of    circular-dependency    document', save=True)
    child = document(title='Document    with    circular    dependency')
    child.parent_topic = parent
    child.save()
    ok_(child.is_child_of(parent))
    grandparent = document(title='Grandparent    of    circular-dependency    document')
    parent.parent_topic = grandparent
    child.save()
    ok_(child.is_child_of(grandparent))
