def test_exch(count):
"""Test exchange method."""
heap = MinHeap()
_ = [heap.insert(randint(0, 100)) for i in range(MAX_ITER)]
pos_a = randint(0, len(heap.heap) - 1)
val_a = heap.heap[pos_a]
pos_b = randint(0, len(heap.heap) - 1)
val_b = heap.heap[pos_b]
heap.exch(val_a, val_b)
assert heap.heap[pos_a] == val_b and heap.heap[pos_b] == val_a
