def test_coloring_sparse():
assert len(coloring(Graph())) == 0
for i in range(1, 21):
g = Graph(range(i))
n_colors = len({c for _, c in coloring(g).items()})
assert n_colors == 1
def g1():
return Graph(range(1, 5), {
(1, 2, 24),
(1, 4, 20),
(3, 1, 3),
(4, 3, 12),
})
def test_color_dot(g):
g = Graph(range(10), zip(range(9), range(1, 10)))
def edge_color(v1, v2, w):
return 'red' if (v1 + v2) > 5 else None
assert to_dot(g, edge_color=edge_color) == g_dot_color
def test_tree_false(g):
assert not is_tree(Graph())
for i in range(MAX):
g.link(i, (i + 1) % MAX)
assert not is_tree(g)
def test_order(g):
gr = Graph()
assert gr.order == 0
for i in range(MAX):
gr.insert(i)
assert gr.order == i + 1
def test_hamiltonian_cycle_raises():
g = Graph(
range(3),
((0, 1), (1, 2)),
)
with pytest.raises(HamiltonianCycleNotFound):
hamiltonian_cycle(g, 1)
def test_set_weight_raises(g):
g = Graph(range(5))
with pytest.raises(KeyError):
g.weight[1, 2] = 5
with pytest.raises(KeyError):
g.weight[42, 2] = 5
def test_dfs():
g = Graph(range(10), zip(range(9), range(1, 10)))
for i in range(10):
r = dfs(g, 0, lambda v: v == i)
assert r == i
assert dfs(g, 0, lambda v: False) is None
def test_cycle_false(g):
assert not has_cycle(Graph())
vertices = list(g.vertices)
for v1, v2 in zip(vertices, vertices[1:]):
g.link(v1, v2, (v1 + v2) % 5)
assert not has_cycle(g)
def test_init():
vertices = {1, 2, 3, 4}
edges = {(1, 2), (2, 3, 10), (3, 4)}
expected_edges = {(1, 2, 1), (2, 3, 10), (3, 4, 1)}
g = Graph(set(vertices), set(edges))
assert g.vertices == vertices
assert g.edges == expected_edges
def test_hamiltonian_cycle():
g = Graph(
range(11),
zip(range(10), range(1, 10)),
)
for v in range(10):
g.link(v, 10, 2)
hc = hamiltonian_cycle(g, 0)
assert hc == list(range(11))
def test_str(g):
g = Graph()
assert str(g) == 'Graph(set(), set())'
g.insert(0)
g.insert(1)
assert str(g) == 'Graph({0, 1}, set())'
g.link(0, 1, 5)
assert str(g) == 'Graph({0, 1}, {(0, 1, 5)})'
def test_kruskal_raises():
g = Graph(range(10))
for v in g.vertices:
g.link(0, v, 5)
for v1 in g.vertices:
for v2 in g.vertices:
if v1 != v2 and not g.has_edge(v1, v2):
g.link(v1, v2, 10)
with pytest.raises(ValueError):
kruskal(g)
def test_connected(g):
assert is_connected(Graph())
assert not is_connected(g)
for i in range(0, MAX, 2):
g.link(i, i + 1)
assert not is_connected(g)
for i in range(1, MAX, 2):
g.link(i, (i + 1) % MAX)
assert is_connected(g)
def test_prim():
g = Graph(range(10))
for v in g.vertices:
if v != 0:
g.link(0, v, 5)
for v1 in g.vertices:
for v2 in g.vertices:
if v1 != v2 and not g.has_edge(v1, v2):
g.link(v1, v2, 10)
tree = prim(g)
assert tree.vertices == set(range(10))
assert tree.edges == {(0, i, 5) for i in range(1, 10)}
def test_regular(g):
assert is_regular(Graph())
assert is_regular(g)
g.link(0, 1)
assert not is_regular(g)
for i in range(1, MAX):
g.link(i, (i + 1) % MAX)
assert is_regular(g)
g.link(1, 3)
assert not is_regular(g)
def g2():
return Graph(
range(9), {
(5, 6, 2),
(1, 2, 8),
(6, 8, 6),
(1, 7, 11),
(2, 5, 4),
(7, 8, 7),
(0, 7, 8),
(6, 7, 1),
(3, 5, 14),
(2, 3, 7),
(3, 4, 9),
(2, 8, 2),
(0, 1, 4),
(4, 5, 10),
})
def test_fringe():
g = Graph(range(10))
g.link(0, 1)
g.link(0, 2)
g.link(0, 3)
g.link(0, 4)
g.link(1, 5)
g.link(1, 6)
g.link(1, 7)
g.link(1, 8)
g.link(2, 9)
assert fringe(g, [0]) == set(range(1, 5))
assert fringe(g, [1]) == {0} | set(range(5, 9))
assert fringe(g, [2]) == {0, 9}
assert fringe(g, [0, 1]) == set(range(2, 9))
assert fringe(g, [0, 1, 2]) == g.vertices - {0, 1, 2}
from itertools import product
import pytest
from context import (Graph, biclique, binary_tree, complete, crown, is_tree,
lattice)
lattice_test1 = Graph(
{
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
20, 21, 22, 23, 24
}, {(0, 1), (2, 7), (17, 18), (5, 6), (4, 9), (6, 7), (8, 9), (10, 15),
(3, 4), (7, 8), (15, 16), (15, 20), (13, 14), (21, 22), (2, 3), (0, 5),
(17, 22), (8, 13), (10, 11), (22, 23), (3, 8), (11, 12), (23, 24),
(6, 11), (14, 19), (12, 17), (1, 2), (16, 17), (18, 23), (5, 10),
(19, 24), (12, 13), (20, 21), (1, 6), (16, 21), (18, 19), (11, 16),
(9, 14), (7, 12), (13, 18)})
lattice_test2 = Graph(
{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19},
{(11, 13), (0, 1), (1, 3), (6, 7), (8, 9), (0, 2), (2, 4), (9, 11), (2, 3),
(14, 15), (8, 10), (10, 12), (10, 11), (4, 5), (16, 17), (5, 7), (17, 19),
(4, 6), (6, 8), (14, 16), (12, 13), (16, 18), (18, 19), (3, 5), (7, 9),
(15, 17), (13, 15), (12, 14)})
lattice_test3 = Graph({0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14},
{(0, 1), (2, 7), (5, 6), (4, 9), (6, 7), (8, 9), (3, 4),
(7, 8), (13, 14), (2, 3), (0, 5), (8, 13), (10, 11),
(3, 8), (11, 12), (6, 11), (1, 2), (5, 10), (12, 13),
(1, 6), (9, 14), (7, 12)})
def test_remove_edge_raises(g):
with pytest.raises(KeyError):
Graph().unlink(0, 1)
def g():
return Graph(range(MAX))
def test_add_edge_raises(g):
with pytest.raises(KeyError):
Graph().link(0, 1)
def test_weighted_dot(g):
g = Graph(range(10), zip(range(9), range(1, 10), [5] * 9))
assert to_dot(g) == g_dot_weighted
def g():
return Graph(range(10), zip(range(9), range(1, 10)))
def test_fringe_raises():
g = Graph()
with pytest.raises(ValueError):
fringe(g, [0])
def test_add_raises(g):
g = Graph()
g.insert(0)
with pytest.raises(KeyError):
g.insert(0)
def test_remove_raises(g):
with pytest.raises(KeyError):
Graph().remove(0)
