def test_weave4(self):
w = Weave()
w.add_revision(1, [], [])
self.assertEquals(w.retrieve_revision(1), [])
w.add_revision(2, ['x'], [1])
self.assertEquals(w.retrieve_revision(2), ['x'])
w.add_revision(3, ['y'], [1])
self.assertEquals(w.retrieve_revision(3), ['y'])
self.assertEquals(w.merge(2, 3), [(['x'], ['y'])])
w.add_revision(4, ['x'], [1])
w.add_revision(5, ['z'], [4])
self.assertEquals(w.merge(2, 5), ['z'])
