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);
}
