@Test
  public void itShouldReturnANullHeadWhenTheListIsFirstCreated() {
    /* Test input */
    LinkedList testList1 = new LinkedList();

    assertNull(testList1.getHead());
  }
 @Test
 public void itAddElementAtTheEndOfListWhenPositionIsNotSpecifiedInAddMethod() {
   /* Test Input */
   LinkedList testInput1 = new LinkedList();
   testInput1.add(5);
   testInput1.add(6);
   testInput1.add(7);
   assertSame(7, testInput1.getTail().getData());
   assertSame(3, testInput1.size());
 }
  @Test
  public void itShouldGetTheProperNode() {
    /* Test Input */
    LinkedList testInput1 = new LinkedList();
    testInput1.add(5);
    testInput1.add(6);
    testInput1.add(7);
    testInput1.add(10);

    assertSame(5, testInput1.get(0));
    assertSame(6, testInput1.get(1));
    assertSame(7, testInput1.get(2));
    assertSame(10, testInput1.get(3));
  }
  @Test
  public void itShouldAddElementIntoExactPositionSpecified() {
    /* Test Input */
    LinkedList testInput1 = new LinkedList();
    testInput1.add(5);
    testInput1.add(6);
    testInput1.add(7);
    testInput1.add(10);

    testInput1.add(4, 19);
    testInput1.add(2, 20);
    assertSame(19, testInput1.get(4));
    assertSame(20, testInput1.get(2));
  }