### Question:
GlobalAddressBook { public String addContact(Contact contact) { throw new UnsupportedOperationException("Not yet implemented"); }  String addContact(Contact contact); List<Contact> getAll(); Contact getContact(String contactId);  }### Answer:
@Test public void testAddContact() { Contact contact = new Contact(); contact.setFirstName("Pedro"); addressBook.addContact(contact); List<Contact> contacts = addressBook.getAll(); assertEquals(1, contacts.size()); assertEquals("Pedro", contacts.get(0).getFirstName()); }