def graph_no_edges():
"""Test graph with nodes only."""
from weighted_graph import Weighted
example_graph = Weighted()
example_graph.add_node('BB')
example_graph.add_node(82)
example_graph.add_node(99)
example_graph.add_node('AA')
return example_graph
def new_weighted_graph():
"""Graph for testing."""
from weighted_graph import Weighted
empty_graph = Weighted()
return empty_graph
def test_graph_init_no_values_taken():
"""Ensure we raise an error if we try to init with a value."""
from weighted_graph import Weighted
with pytest.raises(TypeError):
a_graph = Weighted(2)
def graph_with_edges():
"""Test graph with nodes only."""
from weighted_graph import Weighted
new_graph = Weighted()
new_graph.add_node('A')
new_graph.add_node('B')
new_graph.add_node('C')
new_graph.add_node('D')
new_graph.add_node('E')
new_graph.add_node('F')
new_graph.add_edge('A', 'B')
new_graph.add_edge('A', 'C')
new_graph.add_edge('B', 'D')
new_graph.add_edge('B', 'E')
new_graph.add_edge('C', 'B')
new_graph.add_edge('F', 'A')
new_graph.add_edge('C', 'F')
return new_graph
def test_bellman_with_negatives_two():
"""Ensure it works with various cases of negatives."""
from weighted_graph import Weighted
weighted = Weighted()
weighted.add_node(0)
weighted.add_node(1)
weighted.add_node(2)
weighted.add_node(3)
weighted.add_node(4)
weighted.add_node(5)
weighted.add_edge(0, 1, 5)
weighted.add_edge(0, 2, 3)
weighted.add_edge(1, 3, 7)
weighted.add_edge(2, 3, -2)
weighted.add_edge(3, 0, 8)
weighted.add_edge(3, 4, 3)
weighted.add_edge(4, 5, 6)
weighted.add_edge(0, 5, 4)
assert weighted.bellman_ford(0) == {0: 0, 1: 5, 2: 3, 3: 1, 4: 4, 5: 4}
def test_bellman_ford_with_negatives_one():
"""Ensure bellman works with negatives."""
from weighted_graph import Weighted
weighted = Weighted()
weighted.add_node('S')
weighted.add_node('E')
weighted.add_node('A')
weighted.add_node('D')
weighted.add_node('B')
weighted.add_node('C')
weighted.add_edge('S', 'E', 8)
weighted.add_edge('S', 'A', 10)
weighted.add_edge('E', 'D', 1)
weighted.add_edge('D', 'A', -4)
weighted.add_edge('D', 'C', -1)
weighted.add_edge('A', 'C', 2)
weighted.add_edge('C', 'B', -2)
weighted.add_edge('B', 'A', 1)
assert weighted.bellman_ford('S') == {'A': 5, 'B': 5, 'C': 7, 'D': 9, 'E': 8, 'S': 0}
def test_bellman_ford_first_test_one():
"""Ensure we get same values as dijkstras."""
from weighted_graph import Weighted
new_weighted = Weighted()
new_weighted.add_node('A')
new_weighted.add_node('B')
new_weighted.add_node('C')
new_weighted.add_node('D')
new_weighted.add_node('E')
new_weighted.add_node('F')
new_weighted.add_edge('A', 'B', 7)
new_weighted.add_edge('B', 'C', 9)
new_weighted.add_edge('B', 'E', 4)
new_weighted.add_edge('E', 'D', 2)
new_weighted.add_edge('D', 'C', 2)
new_weighted.add_edge('C', 'F', 6)
new_weighted.add_edge('C', 'A', 1)
assert new_weighted.bellman_ford('A') == {'A': 0, 'B': 7, 'E': 11, 'D': 13, 'C': 15, 'F': 21}
def test_graph_with_nodes_pointing_at_each_other():
"""."""
from weighted_graph import Weighted
new_weighted = Weighted()
new_weighted.add_node('A')
new_weighted.add_node('B')
new_weighted.add_node('C')
new_weighted.add_node('D')
new_weighted.add_node('E')
new_weighted.add_node('F')
new_weighted.add_edge('A', 'B', 7)
new_weighted.add_edge('B', 'C', 9)
new_weighted.add_edge('B', 'E', 4)
new_weighted.add_edge('E', 'D', 2)
new_weighted.add_edge('D', 'C', 2)
new_weighted.add_edge('C', 'F', 6)
new_weighted.add_edge('C', 'A', 1)
assert new_weighted.dijkstra('A') == {'B': 7, 'E': 11, 'D': 13, 'C': 15, 'F': 21}
def dijkstra_alg():
"""Test dijkstra method."""
from weighted_graph import Weighted
new_graph = Weighted()
new_graph.add_node('0')
new_graph.add_node('1')
new_graph.add_node('2')
new_graph.add_node('3')
new_graph.add_node('4')
new_graph.add_node('5')
new_graph.add_edge('0', '1', 1)
new_graph.add_edge('0', '2', 7)
new_graph.add_edge('1', '3', 9)
new_graph.add_edge('1', '5', 15)
new_graph.add_edge('2', '4', 4)
new_graph.add_edge('3', '5', 5)
new_graph.add_edge('3', '4', 10)
new_graph.add_edge('4', '5', 3)
return new_graph
raise KeyError('Node not in graph.')
peeped = []
queue = Queue()
queue.enqueue(start)
while len(queue) > 0:
node = queue.dequeue()
if node not in peeped:
peeped.append(node)
for neighbor in list(graph[node].keys()):
if neighbor not in peeped:
queue.enqueue(neighbor)
return peeped
if __name__ == '__main__':
new_graph = Weighted()
new_graph.add_node('A')
new_graph.add_node('B')
new_graph.add_node('C')
new_graph.add_node('D')
new_graph.add_node('E')
new_graph.add_node('F')
new_graph.add_edge('A', 'B', 1)
new_graph.add_edge('A', 'C', 4)
new_graph.add_edge('B', 'D', 6)
new_graph.add_edge('B', 'E', 8)
new_graph.add_edge('C', 'B', 3)
new_graph.add_edge('F', 'A', 2)
new_graph.add_edge('C', 'F', 7)
print(new_graph)