def test_get_neighbors_none():
graph = Graph()
a = graph.add_node('a')
b = graph.add_node('b')
c = graph.add_node('c')
actual = graph.get_neighbors(a)
assert actual == []
def test_get_neighbors():
graph = Graph()
a = graph.add_node('a')
b = graph.add_node('b')
c = graph.add_node('c')
e_1 = graph.add_edge(a, b, 2)
e_2 = graph.add_edge(a, c, 2)
actual = graph.get_neighbors(a)
assert actual == [e_1, e_2]
def test_get_neighbors_weight():
graph = Graph()
a = graph.add_node('a')
b = graph.add_node('b')
c = graph.add_node('c')
e_1 = graph.add_edge(a, b, 3)
e_2 = graph.add_edge(a, c, 4)
neighbor_1 = graph.get_neighbors(a)[0]
neighbor_2 = graph.get_neighbors(a)[1]
assert neighbor_1.weight == 3 and neighbor_2.weight == 4
def test_one_node_one_edge():
graph = Graph()
a = graph.add_node('a')
edge = graph.add_edge(a, a)
actual = graph.get_neighbors(a)
assert actual == [edge]