public function testCheckInMakesBookAvailable() { $id = UUid::createNew(); $book = new Book($id); $book->checkOut(Uuid::createNew()); $book->checkIn(); $events = $book->getUncommittedChanges()->getIterator()->getArrayCopy(); self::assertInstanceOf(BookCheckedOut::class, $events[0]); self::assertInstanceOf(BookReturned::class, $events[1]); }