### Question:
TransactionManager { synchronized void incrementSequenceNumber(TopicPartition topicPartition, int increment) { Integer currentSequenceNumber = sequenceNumbers.get(topicPartition); if (currentSequenceNumber == null) throw new IllegalStateException("Attempt to increment sequence number for a partition with no current sequence."); currentSequenceNumber += increment; sequenceNumbers.put(topicPartition, currentSequenceNumber); } TransactionManager(String transactionalId, int transactionTimeoutMs, long retryBackoffMs);   TransactionManager(); synchronized TransactionalRequestResult initializeTransactions(); synchronized void beginTransaction(); synchronized TransactionalRequestResult beginCommit(); synchronized TransactionalRequestResult beginAbort(); synchronized TransactionalRequestResult sendOffsetsToTransaction(Map<TopicPartition, OffsetAndMetadata> offsets,
                                                                            String consumerGroupId); synchronized void maybeAddPartitionToTransaction(TopicPartition topicPartition); synchronized void failIfNotReadyForSend(); String transactionalId(); boolean hasProducerId(); boolean isTransactional(); final String logPrefix; }### Answer:
@Test(expected = IllegalStateException.class) public void testInvalidSequenceIncrement() { TransactionManager transactionManager = new TransactionManager(); transactionManager.incrementSequenceNumber(tp0, 3333); }