@Test
  public void testEqualsObjectNotEqual() {
    IntegerList list = new IntegerList(5);
    list.addToTail(6);
    list.addToHead(7);
    list.addToTail(8);

    IntegerList list2 = new IntegerList(5);
    list2.addToHead(4);
    list2.addToHead(7);
    list2.addToTail(8);

    assertFalse(list.equals(list2));
  }
 @Test
 public void testGetSize() {
   IntegerList list = new IntegerList(5);
   list.addToTail(6);
   list.addToHead(7);
   list.addToTail(8);
   assertEquals(4, list.getSize());
 }
 @Test
 public void testAddToHead() {
   IntegerList list = new IntegerList(5);
   list.addToHead(7);
   list.addToHead(6);
   assertEquals(6, list.getHeadValue());
   assertEquals(5, list.getTailValue());
 }
  @Test
  public void testContains() {
    IntegerList list = new IntegerList(5);
    list.addToTail(6);
    list.addToHead(7);
    list.addToTail(8);
    assertTrue(list.contains(5));

    assertTrue(list.contains(6));

    assertTrue(list.contains(7));

    assertTrue(list.contains(8));

    assertFalse(list.contains(42));
  }