def test_pq_pop_when_empty():
"""Ensures that an exception is raised when trying
to pop() from an empty priority heap.
"""
pq = PriorityQueue()
with pytest.raises(IndexError):
pq.pop()
def test_peek(create_pq):
"""Ensures that peek raises an error when the priority queue
is empty, and that it returns the right value when items are added.
"""
pq = PriorityQueue()
with pytest.raises(IndexError):
pq.peek()
pq = create_pq
pq.insert(100, "This is so much fun!")
assert pq.peek() == "This is so much fun!"
assert pq.peek() != "This sucks"
def test_pop_single(create_pq):
pq = PriorityQueue()
pq.insert(1, "Almost missed this")
assert pq.pop() == "Almost missed this"
def create_pq():
"""Creates a priotity queue, then inserts priorities and values to use
for further testing.
"""
pq = PriorityQueue()
pq.insert(1, "We")
pq.insert(2, "eee")
pq.insert(1, "eee")
pq.insert(3, "are")
pq.insert(1, "the")
pq.insert(4, "champions")
pq.insert(1, "my")
pq.insert(5, "friends")
return pq
def test_pq_insert2():
"""Test that inserting into a priority queue
behaves as expected.
"""
pq = PriorityQueue()
pq.insert(1, "We")
assert pq.heap[0].value == "We"
pq.insert(2, "eee")
assert pq.heap[0].value == "eee"
pq.insert(1, "eee")
assert pq.heap[0].value == "eee"
pq.insert(3, "are")
assert pq.heap[0].value == "are"
pq.insert(1, "the")
assert pq.heap[0].value == "are"
pq.insert(4, "champions")
assert pq.heap[0].value == "champions"
pq.insert(1, "my")
assert pq.heap[0].value == "champions"
pq.insert(5, "friends")
assert pq.heap[0].value == "friends"