### Question:
Profile { public void update(String displayName, TeeShirtSize teeShirtSize) { if (displayName != null) { this.displayName = displayName; } if (teeShirtSize != null) { this.teeShirtSize = teeShirtSize; } } private  Profile();  Profile(String userId, String displayName, String mainEmail, TeeShirtSize teeShirtSize); String getUserId(); String getDisplayName(); String getMainEmail(); TeeShirtSize getTeeShirtSize(); List<String> getConferenceKeysToAttend(); void update(String displayName, TeeShirtSize teeShirtSize); void addToConferenceKeysToAttend(String conferenceKey); void unregisterFromConference(String conferenceKey);  }### Answer:
@Test public void testUpdate() throws Exception { String newDisplayName = "Kay's Daddy"; TeeShirtSize newTeeShirtSize = TeeShirtSize.M; profile.update(newDisplayName, newTeeShirtSize); assertEquals(USER_ID, profile.getUserId()); assertEquals(newDisplayName, profile.getDisplayName()); assertEquals(EMAIL, profile.getMainEmail()); assertEquals(newTeeShirtSize, profile.getTeeShirtSize()); }