def test_dublicate_values_to_a_weight_graph_adds_some_nodes(num):
"""Test that adding duplicate values to the graph add only unique items."""
from weight_graph import Graph
g = Graph()
for x in range(num):
g.add_node(x % 5)
assert len(g.nodes()) == 5 if num > 5 else num
def test_has_node(node, n, result):
"""Test to check if a node exists in graph."""
from weight_graph import Graph
g = Graph()
for idx in node:
g.add_node(idx)
assert g.has_node(n) == result
def test_adding_unique_values_to_a_weight_graph_adds_all_nodes(num):
"""Test that adding unique values to the graph adds all of them."""
from weight_graph import Graph
g = Graph()
for x in range(num):
g.add_node(x)
assert len(g.nodes()) == num
def test_del_nodes(node, result):
"""Test to check the deleted nodes aren't there."""
from weight_graph import Graph
g = Graph()
for idx in node:
g.add_node(idx)
assert g.del_node(1) == result
def test_nodes(node, result):
"""Test to check if all nodes are there."""
from weight_graph import Graph
g = Graph()
for idx in node:
g.add_node(idx)
assert g.nodes() == result
def test_nodes_of_filled_weight_graph_has_all_nodes(num):
"""Test that nodes lists all the nodes in a graph."""
from weight_graph import Graph
g = Graph()
for x in range(num):
g.add_node(x)
assert len(g.nodes()) == num
assert sorted(g.nodes()) == list(range(num))
def test_has_node_returns_true_if_node_serched_is_in_weight_graph(num):
"""Test that has node returns true if looking for node present in weight graph."""
from weight_graph import Graph
g = Graph()
for x in range(num):
g.add_node(x)
for x in range(num):
assert g.has_node(x)
def test_edge(node, result):
"""Test to check if all edges are there."""
from weight_graph import Graph
g = Graph()
for idx in node:
g.add_node(idx)
g.add_edge(2, 3)
g.add_edge(1, 4)
assert g.edges() == result
def test_neighbor(node, n, result):
"""Test to check that the correct node have the right edge."""
from weight_graph import Graph
g = Graph()
for idx in node:
g.add_node(idx)
g.add_edge(1, 1)
g.add_edge(1, 4)
g.add_edge(4, 2)
g.add_edge(3, 5)
assert g.neighbors(n) == result
from heapq import heappop, heappush
def dijkstra(graph, start, target):
unique = count()
visited = set()
heap = [(0, unique, start, ())]
while heap:
weight, junk, node, path = heappop(heap)
if node == target:
return weight, path
if node not in visited:
visited.add(node)
for neighbor, edge in graph[node].items():
heappush(heap, (weight + edge, next(unique),
neighbor, (neighbor, path)))
if __name__ == '__main__':
g = Graph()
g.add_node('A')
g.add_node('B')
g.add_node('C')
g.add_node('D')
g.add_edge('A', 'B', 4)
g.add_edge('A', 'C', 20)
g.add_edge('B', 'D', 5)
g.add_edge('C', 'D', 200)
dijkstra(g, 'A', 'D')