def test_child_index(self):
heap = MinHeap()
assert heap._left_child_index(0) == 1
assert heap._right_child_index(0) == 2
assert heap._left_child_index(1) == 3
assert heap._right_child_index(1) == 4
assert heap._left_child_index(2) == 5
assert heap._right_child_index(2) == 6
assert heap._left_child_index(3) == 7
assert heap._right_child_index(3) == 8
assert heap._left_child_index(4) == 9
assert heap._right_child_index(4) == 10
assert heap._left_child_index(5) == 11
assert heap._right_child_index(5) == 12
assert heap._left_child_index(6) == 13
assert heap._right_child_index(6) == 14
