// Check the stack is initially empty.
	if LFStackPop(stack) != nil {
		t.Fatalf("stack is not empty")
	}

	// Push one element.
	node := allocMyNode(42)
	LFStackPush(stack, fromMyNode(node))

	// Push another.
	node = allocMyNode(43)
	LFStackPush(stack, fromMyNode(node))

	// Pop one element.
	node = toMyNode(LFStackPop(stack))
	if node == nil {
		t.Fatalf("stack is empty")
	}
	if node.data != 43 {