def test_add_connect(self):
g = Graph(directed=True)
g.add_vertices(1, 2, 3)
g.connect(1, 2)
g.connect(2, 3)
self.assertEqual(g.Vertices, {1, 2, 3})
self.assertEqual(g.Edges, {(1, 2), (2, 3)})
self.assertEqual(g._successors, {1: {2}, 2: {3}, 3: set()})
self.assertEqual(g._antecessors, {1: set(), 2: {1}, 3: {2}})
def test_constructor_undirected(self):
g = Graph(directed=False)
g.add_vertices(1, 2, 3)
g.connect(1, 2)
g.connect(2, 3)
h = Graph({1, 2, 3}, {(1, 2), (2, 1), (2, 3), (3, 2)}, directed=False)
self.assertEqual(g.Vertices, h.Vertices)
self.assertEqual(g.Edges, h.Edges)
self.assertEqual(g._successors, h._successors)
self.assertEqual(g._antecessors, h._antecessors)
