def test_size_fail():
graph = Graph()
a = graph.add_node('a')
b = graph.add_node('b')
expected = 3
actual = graph.size()
assert actual != expected
def test_graph_missing_start_vertex():
"""
A walk of a graph without a starting vertex sees no vertices.
"""
graph = Graph()
graph.add_node('c')
vertex = None
expected = set({})
actual = depth_first(graph, vertex)
assert actual == expected
def test_breadth_first_circle_start_a():
graph = Graph()
a = graph.add_node('a')
b = graph.add_node('b')
c = graph.add_node('c')
graph.add_edge(a, b)
graph.add_edge(b, c)
graph.add_edge(c, a)
actual = graph.breadth_first(a)
expected = ['a', 'b', 'c']
assert actual == expected
def test_graph_only_islands():
"""
A walk of a graph of islands sees only the starting vertex.
"""
graph = Graph()
graph.add_node('a')
graph.add_node('b')
c = graph.add_node('c')
vertex = c
expected = {
c,
}
actual = depth_first(graph, vertex)
assert actual == expected
def test_get_neighbor():
graph = Graph()
a = graph.add_node('a')
b = graph.add_node('b')
c = graph.add_node('c')
graph.add_edge(a, b)
graph.add_edge(b, a)
graph.add_edge(b, c)
actual = graph.get_neighbor(b)
expected = [('a', 1), ('c', 1)]
assert actual == expected
def test_get_nodes():
graph = Graph()
a = graph.add_node('a')
b = graph.add_node('b')
c = graph.add_node('c')
graph.add_edge(a, b)
actual = graph.get_nodes()
expected = ['a', 'b', 'c']
assert actual == expected
def test_graph_no_vertices():
"""
A walk of a graph with no vertices sees no vertices.
"""
graph = Graph()
vertex = None
expected = set({})
actual = depth_first(graph, vertex)
assert actual == expected
def test_graph_empty():
"""
Trip through empty can't happen.
"""
graph = Graph()
cities = ['a', 'b', 'c']
expected = 'False:$0'
actual = get_edge(graph, cities)
assert actual == expected
def test_one_node_and_edge():
graph = Graph()
a = graph.add_node('a')
graph.add_edge(a, a)
actual = graph.get_neighbor(a)
expected = [('a', 1)]
assert actual == expected
def test_get_nodes_with_empty_graph():
g = Graph()
actual = g.get_nodes()
expected = 'NULL'
assert actual == expected
def test_add_edge_true():
graph = Graph()
a = graph.add_node('a')
b = graph.add_node('b')
graph.add_edge(a, b)
assert True
def test_add_node():
graph = Graph()
expected = 'a'
actual = graph.add_node('a').value
assert expected == actual
def test_breadth_first_code_challenge_example():
graph = Graph()
a = graph.add_node('Pandora')
b = graph.add_node('Arendelle')
c = graph.add_node('Metroville')
d = graph.add_node('Monstropolis')
e = graph.add_node('Naboo')
f = graph.add_node('Narnia')
graph.add_edge(a, b)
graph.add_edge(b, d)
graph.add_edge(b, c)
graph.add_edge(c, d)
graph.add_edge(c, e)
graph.add_edge(c, f)
graph.add_edge(f, e)
actual = graph.breadth_first(a)
expected = [
'Pandora', 'Arendelle', 'Monstropolis', 'Metroville', 'Naboo', 'Narnia'
]
assert actual == expected
def test_graph_with_edges():
"""
A walk of a graph with edges sees many vertices.
"""
graph = Graph()
a = graph.add_node('a')
b = graph.add_node('b')
c = graph.add_node('c')
d = graph.add_node('d')
e = graph.add_node('e')
f = graph.add_node('f')
g = graph.add_node('g')
h = graph.add_node('h')
graph.add_edge(a, b)
graph.add_edge(a, d)
graph.add_edge(b, a)
graph.add_edge(b, c)
graph.add_edge(b, d)
graph.add_edge(c, b)
graph.add_edge(c, h)
graph.add_edge(d, a)
graph.add_edge(d, b)
graph.add_edge(d, e)
graph.add_edge(d, f)
graph.add_edge(d, g)
graph.add_edge(e, d)
graph.add_edge(f, d)
graph.add_edge(f, g)
graph.add_edge(g, d)
graph.add_edge(g, f)
graph.add_edge(h, c)
expected = {a, b, c, h, d, e, f, g}
actual = depth_first(graph, a)
assert actual == expected
def graph():
"""
Graph instance.
"""
graph = Graph()
a = graph.add_node('a')
b = graph.add_node('b')
c = graph.add_node('c')
d = graph.add_node('d')
e = graph.add_node('e')
f = graph.add_node('f')
graph.add_edge(a, b, 150)
graph.add_edge(a, c, 82)
graph.add_edge(b, a, 150)
graph.add_edge(b, c, 99)
graph.add_edge(b, d, 42)
graph.add_edge(c, a, 82)
graph.add_edge(c, b, 99)
graph.add_edge(c, d, 105)
graph.add_edge(c, e, 37)
graph.add_edge(c, f, 26)
graph.add_edge(d, b, 42)
graph.add_edge(d, c, 105)
graph.add_edge(d, f, 73)
graph.add_edge(e, c, 37)
graph.add_edge(e, f, 250)
graph.add_edge(f, c, 26)
graph.add_edge(f, d, 73)
graph.add_edge(f, e, 250)
return graph