def test_sssp():
# sssp = single source shortest path
# CLRS(2009) p659
g = Graph()
g.add_edge(Edge("s", "t", 10))
g.add_edge(Edge("s", "y", 5))
g.add_edge(Edge("t", "y", 2))
g.add_edge(Edge("t", "x", 1))
g.add_edge(Edge("x", "z", 4))
g.add_edge(Edge("z", "x", 6))
g.add_edge(Edge("z", "s", 7))
g.add_edge(Edge("y", "t", 3))
g.add_edge(Edge("y", "x", 9))
g.add_edge(Edge("y", "z", 2))
d, p = g.dijkstra("s")
assert d["s"] == 0 and p["s"] is None
assert d["t"] == 8 and p["t"] == "y"
assert d["x"] == 9 and p["x"] == "t"
assert d["z"] == 7 and p["z"] == "y"
assert d["y"] == 5 and p["y"] == "s"
d, p = g.bellmanford("s")
assert d["s"] == 0 and p["s"] is None
assert d["t"] == 8 and p["t"] == "y"
assert d["x"] == 9 and p["x"] == "t"
assert d["z"] == 7 and p["z"] == "y"
assert d["y"] == 5 and p["y"] == "s"
def test_bellmanford():
g = Graph()
g.add_edge(Edge("a", "x", 1))
g.add_edge(Edge("x", "y", -1))
g.add_edge(Edge("y", "z", -1))
g.add_edge(Edge("z", "x", -1))
d, p = g.bellmanford("a")
assert d["a"] == 0 and p["a"] is None
assert d["x"] == -np.inf and p["x"] == "z"
assert d["y"] == -np.inf and p["y"] == "x"
assert d["z"] == -np.inf and p["z"] == "y"
