def test_delete_from_one_element_heap():
heap = Heap([1])
heap.delete()
expected = [0]
output = heap.heap
assert output == expected
def test_delete_from_empty_heap():
heap = Heap()
heap.delete()
expected = [0]
output = heap.heap
assert output == expected
def test_delete_from_full_heap():
heap = Heap([9, 7, 5, 6, 2])
deleted_node = heap.delete()
expected = [0, 7, 6, 5, 2]
output = heap.heap
assert output == expected
assert deleted_node == 9
def test_delete_from_two_element_heap():
heap = Heap([5, 1])
deleted_node = heap.delete()
expected = [0, 1]
output = heap.heap
assert output == expected
assert deleted_node == 5
