def test_empty_heap_creation():
heap = IndexedHeap()
assert len(heap) == 0, 'The length should be equal to 0'
assert len(heap) == len(
list(heap),
), 'The length should be exact as the number of the stored elements'
assert heap.pop_first() == (None, None), 'Pop oeration should return None'
def dijkstra_shortest_paths(adj_list, node_from, infinity_value=0xFFFFFFFF):
distances = {k: infinity_value for k in get_nodes(adj_list)}
distances[node_from] = 0
visit_queue = IndexedHeap(distances)
next_edge, distance = visit_queue.pop_first()
while next_edge is not None:
for edge in get_edges_from(adj_list, next_edge):
if edge[0] in visit_queue and (distances[edge[0]] >
distance + edge[1]):
distances[edge[0]] = distance + edge[1]
visit_queue.update({edge[0]: distances[edge[0]]})
next_edge, distance = visit_queue.pop_first()
return distances
def test_heap_reversed_order():
test_values = {1: 4, 2: 2, 4: 1, 5: 5}
heap = IndexedHeap(test_values, reverse=True)
assert is_heap(
list(heap),
start_position=0,
compare_fn=lambda first, second: first[1] >= second[1],
), 'Max heap should be created'
assert (
heap.pop_first(),
heap.pop_first(),
heap.pop_first(),
heap.pop_first(),
) == (
(5, 5), (1, 4), (2, 2), (4, 1)
), 'The items should be poped in sorted order'
def test_heap_default_order():
test_values = {1: 4, 2: 2, 3: 3, 4: 1, 5: 5}
heap = IndexedHeap(test_values)
assert is_heap(
list(heap),
start_position=0,
compare_fn=lambda first, second: first[1] <= second[1],
), 'Min heap should be created by default'
assert (
heap.pop_first(),
heap.pop_first(),
heap.pop_first(),
heap.pop_first(),
heap.pop_first(),
) == (
(4, 1), (2, 2), (3, 3), (1, 4), (5, 5),
), 'The items should be poped in sorted order'