public void AddTwoListNodesTest() { ListNode firstNumber = new ListNode(7); firstNumber.Next = new ListNode(4); firstNumber.Next.Next = new ListNode(4); ListNode secondNumber = new ListNode(5); secondNumber.Next = new ListNode(3); secondNumber.Next.Next = new ListNode(6); ListNode answerOne = ListNode.AddTwoNumbers(firstNumber, secondNumber); Assert.IsTrue(answerOne.Val == 2); Assert.IsTrue(answerOne.Next.Val == 8); Assert.IsTrue(answerOne.Next.Next.Val == 0); Assert.IsTrue(answerOne.Next.Next.Next.Val == 1); Assert.IsTrue(answerOne.Next.Next.Next.Next == null); ListNode thirdNumber = new ListNode(1); thirdNumber.Next = new ListNode(2); thirdNumber.Next.Next = new ListNode(3); thirdNumber.Next.Next.Next = new ListNode(4); thirdNumber.Next.Next.Next.Next = new ListNode(5); ListNode fourthNumber = new ListNode(6); fourthNumber.Next = new ListNode(7); fourthNumber.Next.Next = new ListNode(8); fourthNumber.Next.Next.Next = new ListNode(9); ListNode answerTwo = ListNode.AddTwoNumbers(thirdNumber, fourthNumber); Assert.IsTrue(answerTwo.Val == 7); Assert.IsTrue(answerTwo.Next.Val == 9); Assert.IsTrue(answerTwo.Next.Next.Val == 1); Assert.IsTrue(answerTwo.Next.Next.Next.Val == 4); Assert.IsTrue(answerTwo.Next.Next.Next.Next.Val == 6); }