public void TestIntersection()
{
// Arrange
// either null
SLLNode nullHead1 = null;
SLLNode nullHead2 = new SLLNode(1);
// first
SLLNode firstHead1 = new SLLNode(99);
SLLNode firstHead2 = firstHead1;
// common case intersection
SLLNode commonCase1 = new SLLNode(2);
SLLNode commonCaseNext1 = new SLLNode(3);
commonCase1.Next = commonCaseNext1;
SLLNode commonCaseNextNext1 = new SLLNode(4);
commonCaseNext1.Next = commonCaseNextNext1;
SLLNode commonCaseNextNextNext1 = new SLLNode(5);
commonCaseNextNext1 = commonCaseNextNextNext1;
SLLNode commonCase2 = new SLLNode(10);
SLLNode commonCaseNext2 = new SLLNode(11);
commonCase2.Next = commonCaseNext2;
commonCaseNext2.Next = commonCaseNextNext1;
// no intersection
SLLNode noIntersectionHead1 = new SLLNode(30);
SLLNode noIntersectionHead2 = new SLLNode(40);
noIntersectionHead1.AddToTail(53);
noIntersectionHead2.AddToTail(64);
// Act
SLLNode nullHeadResult = LinkedLists.Instersection(nullHead1, nullHead2);
SLLNode firstHeadResult = LinkedLists.Instersection(firstHead1, firstHead2);
SLLNode commonCaseResult = LinkedLists.Instersection(commonCase1, commonCase2);
SLLNode noIntersectionResult = LinkedLists.Instersection(noIntersectionHead1, noIntersectionHead2);
// Assert
Assert.IsNull(nullHeadResult);
Assert.AreEqual(firstHeadResult, firstHead1);
Assert.ReferenceEquals(commonCaseResult, commonCaseNextNext1);
Assert.IsNull(noIntersectionResult);
}