### Question:
TransactionSet { public List<Transaction> getTransactions() { return transactionsByHash.values().stream() .collect(Collectors.collectingAndThen(Collectors.toList(), Collections::unmodifiableList)); } TransactionSet();  TransactionSet(TransactionSet transactionSet);  TransactionSet(Map<Keccak256, Transaction> transactionsByHash, Map<UscAddress, List<Transaction>> transactionsByAddress); void addTransaction(Transaction transaction); boolean hasTransaction(Transaction transaction); void removeTransactionByHash(Keccak256 hash); List<Transaction> getTransactions(); List<Transaction> getTransactionsWithSender(UscAddress senderAddress);  }### Answer:
@Test public void getEmptyTransactionList() { TransactionSet txset = new TransactionSet(); List<Transaction> result = txset.getTransactions(); Assert.assertNotNull(result); Assert.assertTrue(result.isEmpty()); }