def test_get_edge_weight(self):
v_1 = Vertex('A')
# add a neighbor without weight
v_2 = Vertex('B')
v_1.add_neighbor(v_2, 3)
assert v_2 in v_1.neighbors
assert len(v_1.get_neighbors()) is 1
# check the weight
self.assertEqual(v_1.get_edge_weight(v_2), 3)
def test_add_neighbor(self):
vertex_1 = Vertex('A')
# add a neighbor without weight
vertex_2 = 'B'
vertex_1.add_neighbor(vertex_2)
assert vertex_2 in vertex_1.neighbors
assert len(vertex_1.get_neighbors()) is 1
assert vertex_1.get_edge_weight(vertex_2) is 0
# add another vertex with weight
vertex_3 = 'C'
vertex_1.add_neighbor(vertex_3, 5)
assert vertex_3 in vertex_1.neighbors
assert len(vertex_1.get_neighbors()) is 2
assert vertex_1.get_edge_weight(vertex_3) is 5
# adding duplicate neighbor
vertex_1.add_neighbor(vertex_2, 3)
assert vertex_2 in vertex_1.neighbors
assert len(vertex_1.get_neighbors()) is 2
assert vertex_1.get_edge_weight(vertex_2) is 3