// exception expected
  @Test
  public void testPeekFrontEmpty() throws InvalidAccessException, ValueException {

    DoubleLinkedList dll = new DoubleLinkedList();
    try {
      dll.peekFront();
    } catch (InvalidAccessException ex) {
      return;
    }
    fail("ExceptionExpected");
  }
  // no Exception expected
  @Test
  public void testPeekFront() throws InvalidAccessException, ValueException {

    DoubleLinkedList dll = new DoubleLinkedList();
    dll.pushFront(5);
    dll.pushFront(6);
    try {
      assertEquals(6, dll.peekFront());
    } catch (InvalidAccessException ex) {
      fail(ex.getMessage());
    }
  }