testing.md

Tests

TwTkms also provides helpers for conducting end-to-end integration tests.

For that, you can add a dependency:

testImplementation 'com.transferwise.kafka:tw-tkms-test-starter'

And you will get the following beans:

@Autowired
protected ITkmsSentMessagesCollector tkmsSentMessagesCollector;
@Autowired
protected ITkmsRegisteredMessagesCollector tkmsRegisteredMessagesCollector;
@Autowired
protected ITkmsTestDao tkmsTestDao

Consult those classes' JavaDocs for more information about usage.

Usually you are using only ITkmsSentMessagesCollector though.

But ITkmsRegisteredMessagesCollector can be useful, if you have transactional tests which get rolled back at the end.

For example:

public PayoutBatchStateChangedEvent waitForNinjasHasReceivedBatchStateChange(Long batchId) {
    return await().until(() -> {
        List<PayoutBatchStateChangedEvent> sentKafkaMessages = tkmsSentMessagesCollector.getSentJsonMessages(
                PAYOUT_BATCH_STATE_CHANGED, PayoutBatchStateChangedEvent.class);

        List<PayoutBatchStateChangedEvent> list = sentKafkaMessages.stream().filter((m) -> m.getBatchId().equals(batchId)).collect(Collectors.toList());
        return list.size() == 1 ? list.get(0) : null;
    }, Objects::nonNull);
}

Make sure, you are cleaning the memory regularly. For example after (or before) each test:

tkmsRegisteredMessagesCollector.clear()
tkmsSentMessagesCollector.clear()

If you don't, TwTkms will start yelling at you.