def test_add_regular_edges_invalid(self):
g = Graph([v, w, x])
# degree > vertexcount-1
with pytest.raises(GraphException):
g.add_regular_edges(3)
# degree * vertexcount not even
with pytest.raises(GraphException):
g.add_regular_edges(1)
def test_add_regular_edges_0(self):
g = Graph()
g.add_regular_edges(0)
assert g.vertices() == []
assert g.edges() == []
g = Graph([v, w, x])
g.add_regular_edges(0)
assert sorted(g.vertices()) == sorted([v, x, w])
assert g.edges() == []
def test_add_regular_edges_negative(self):
g = Graph()
with pytest.raises(ValueError):
g.add_regular_edges(-1)
def test_add_regular_edges_odd(self):
g = Graph([v, w, x, y])
g.add_regular_edges(1)
def test_add_regular_edges_even(self):
g = Graph([v, w, x])
g.add_regular_edges(2)
assert set(g.edges()) == set([vw, vx, wx])