def test_neighbors():
g = Graph()
g.add_edge('a', 'b')
g.add_edge('b', 'c')
g.add_edge('a', 'c')
neighbors = g.neighbors('a')
assert 'b' in neighbors
assert 'c' in neighbors
try:
g.neighbors('q')
except IndexError:
assert True
else:
assert False
def test_adjacent():
g = Graph()
g.add_edge('a', 'b')
g.add_edge('a', 'c')
try:
g.adjacent('a', 'e')
except IndexError:
assert True
else:
assert False
assert g.adjacent('a', 'b') is True
assert g.adjacent('c', 'b') is False
def test_has_node():
g = Graph()
assert g.has_node('a') is False
g.add_node('a')
assert g.has_node('a') is True
g.add_edge('b', 'c')
assert g.has_node('b') is True
g.del_edge('b', 'c')
assert g.has_node('c') is True
def test_delete_node():
g = Graph()
try:
g.delete_node('a')
except IndexError:
assert True
else:
assert False
for letter in ['a', 'b', 'c', 'd']:
g.add_node(letter)
g.add_edge('a', 'b')
g.add_edge('b', 'c')
g.add_edge('a', 'c')
g.add_edge('b', 'd')
g.delete_node('d')
for edge in g._edges:
assert 'd' not in edge.connects
assert len(g._edges) == 3
g.delete_node('a')
assert len(g._edges) == 1
for edge in g._edges:
assert edge.connects == {'b', 'c'}
def test_init():
g = Graph()
assert len(g._edges) == 0
assert len(g._nodes) == 0
def test_del_edge():
g = Graph()
e1 = Edge('a', 'b')
e2 = Edge('b', 'c')
e3 = Edge('a', 'c')
edges = [e1, e2, e3]
g.add_edge('a', 'b')
g.add_edge('b', 'c')
g.add_edge('a', 'c')
for edge in edges:
assert edge in g._edges
g.del_edge('b', 'c')
assert len(g._edges) == 2
assert e2 not in g._edges
assert e1 in g._edges and e3 in g._edges
try:
g.del_edge(1, 2)
except IndexError:
assert True
else:
assert False
g.del_edge('b', 'a')
assert len(g._edges) == 1
def test_add_edge():
g = Graph()
g.add_node(1)
g.add_edge(3, 2)
assert len(g.nodes()) == 3
assert ({3, 2}, 1) in g.edges()
def test_weighted_edges():
g = Graph()
g.add_edge('a', 'b')
g.add_edge('a', 'd')
g.add_edge('a', 'g')
g.add_edge('b', 'e')
g.add_edge('e', 'g')
g.add_edge('b', 'f')
g.add_edge('f', 'd')
g.add_edge('f', 'c')
g.add_edge('c', 'h')
assert g.adjacent('a', 'b') is True
assert g.adjacent('a', 'c') is False
g.del_edge('a', 'b')
assert g.neighbors('a') == ['d', 'g']
def test_bfs():
g = Graph()
g.add_edge('a', 'b')
g.add_edge('a', 'd')
g.add_edge('a', 'g')
g.add_edge('b', 'e')
g.add_edge('e', 'g')
g.add_edge('b', 'f')
g.add_edge('f', 'd')
g.add_edge('f', 'c')
g.add_edge('c', 'h')
assert g.bfs('a') == ['a', 'b', 'd', 'g', 'e', 'f', 'c', 'h']
def test_dfs():
g = Graph()
g.add_edge('a', 'b')
g.add_edge('b', 'c')
g.add_edge('c', 'd')
g.add_edge('d', 'e')
assert g.dfs('a') == ['a', 'b', 'c', 'd', 'e']
g.add_edge('a', 'e')
assert g.dfs('a') == ['a', 'b', 'c', 'd', 'e']
g = Graph()
g.add_edge('a', 'b')
g.add_edge('a', 'c')
g.add_edge('a', 'd')
assert len(g.dfs('a')) == 4
for item in ['a', 'b', 'c', 'd']:
assert item in g.dfs('a')
assert g.dfs('b')[:2] == ['b', 'a']
try:
g.dfs('h')
except IndexError:
assert True
else:
assert False
def test_add_vertex():
g = Graph()
g.add_node(1)
g.add_node(2)
assert 1 in g.nodes()
assert 2 in g.nodes()