def test_source_components(self):
# Single source consisting of two objects.
a, b, c, d = ["A"], ["B"], ["C"], ["D"]
a.append(b)
b.append(a)
c.append(d)
d.append(c)
b.append(d)
graph = ObjectGraph([a, b, c, d])
sources = graph.source_components()
self.assertEqual(len(sources), 1)
source = sources[0]
self.assertIn(a, source)
self.assertIn(b, source)
self.assertNotIn(c, source)
self.assertNotIn(d, source)
# Single source consisting of one object.
a, b, c, d = ["A"], ["B"], ["C"], ["D"]
a.append(b)
b.append(d)
c.append(a)
graph = ObjectGraph([a, b, c, d])
sources = graph.source_components()
self.assertEqual(len(sources), 1)
source = sources[0]
self.assertNotIn(a, source)
self.assertNotIn(b, source)
self.assertIn(c, source)
self.assertNotIn(d, source)
# Multiple sources.
a, b, c, d, e, f = ["A"], ["B"], ["C"], ["D"], ["E"], ["F"]
a.append(b)
b.append(d)
c.append(a)
e.append(d)
graph = ObjectGraph([a, b, c, d, e, f])
sources = graph.source_components()
self.assertEqual(len(sources), 3)
