/** Tests the unsubscribe function */
  public void testUnsubscribe() {
    Subscriber subscriber = new Subscriber("*****@*****.**", "myPassword");
    Newsletter newsletter = new Newsletter("BFH Newsletter", "blablabla", 6);

    newsletter.subscribe(subscriber);
    newsletter.unsubscribe(subscriber);
    assertFalse(newsletter.hasNewsletterSubscription(subscriber));
  }