### Question:
Conference { public void bookSeats(final int number) { if (seatsAvailable < number) { throw new IllegalArgumentException("There are no seats available."); } seatsAvailable = seatsAvailable - number; } private  Conference();  Conference(final long id, final String organizerUserId,
                      final ConferenceForm conferenceForm); long getId(); String getName(); String getDescription(); @ApiResourceProperty(ignored = AnnotationBoolean.TRUE) Key<Profile> getProfileKey(); String getWebsafeKey(); @ApiResourceProperty(ignored = AnnotationBoolean.TRUE) String getOrganizerUserId(); String getOrganizerDisplayName(); List<String> getTopics(); String getCity(); Date getStartDate(); Date getEndDate(); int getMonth(); int getMaxAttendees(); int getSeatsAvailable(); void updateWithConferenceForm(ConferenceForm conferenceForm); void bookSeats(final int number); void giveBackSeats(final int number); @Override String toString();  }### Answer:
@Test public void testBookSeats() throws Exception { Conference conference = new Conference(ID, ORGANIZER_USER_ID, conferenceForm); conference.bookSeats(1); assertEquals(CAP - 1, conference.getSeatsAvailable()); }