def test_adjacent_node_not_found():
g = Graph()
g.add_edge(u"A", u"C")
with pytest.raises(KeyError):
g.adjacent(u"B", u"D")
g.adjacent(u"A", u"D")
g.adjacent(u"B", u"C")
def test_adjacent():
g = Graph()
g.add_edge(u"A", u"C")
g.add_node(u"B")
print g.edges()
assert g.adjacent(u"A", u"C") is True
assert g.adjacent(u"C", u"A") is True
assert g.adjacent(u"B", u"C") is False
assert g.adjacent(u"B", u"A") is False
with pytest.raises(KeyError):
g.adjacent(u"A", u"D")
