from dijkstra import dijkstra

def test_basic():
    g = {"a": [("b", 1), ("c", 4)], "b": [("c", 2)], "c": []}
    d = dijkstra(g, "a")
    assert d["a"] == 0 and d["b"] == 1 and d["c"] == 3

def test_unreachable():
    g = {"a": [], "b": []}
    d = dijkstra(g, "a")
    assert d["b"] == float("inf")

def test_unknown_src():
    try:
        dijkstra({"a": []}, "z")
        raise AssertionError("expected")
    except ValueError:
        pass

def test_negative():
    try:
        dijkstra({"a": [("b", -1)]}, "a")
        raise AssertionError("expected")
    except ValueError:
        pass

if __name__ == "__main__":
    for n in [x for x in globals() if x.startswith("test_")]:
        globals()[n]()
        print("PASS", n)
    print("ALL PASS")