@Test
    public void testReturnCommittedTransactions() {
        buildFetcher(OffsetResetStrategy.EARLIEST, new ByteArrayDeserializer(),
                new ByteArrayDeserializer(), Integer.MAX_VALUE, IsolationLevel.READ_COMMITTED);
        ByteBuffer buffer = ByteBuffer.allocate(1024);
        int currentOffset = 0;

        currentOffset += appendTransactionalRecords(buffer, 1L, currentOffset,
                new SimpleRecord(time.milliseconds(), "key".getBytes(), "value".getBytes()),
                new SimpleRecord(time.milliseconds(), "key".getBytes(), "value".getBytes()));

        commitTransaction(buffer, 1L, currentOffset);
        buffer.flip();

        MemoryRecords records = MemoryRecords.readableRecords(buffer);
        assignFromUser(singleton(tp0));

        subscriptions.seek(tp0, 0);

        // normal fetch
        assertEquals(1, sendFetches());
        assertFalse(fetcher.hasCompletedFetches());
        client.prepareResponse(body -> {
            FetchRequest request = (FetchRequest) body;
            assertEquals(IsolationLevel.READ_COMMITTED, request.isolationLevel());
            return true;
        }, fullFetchResponseWithAbortedTransactions(records, Collections.emptyList(), Errors.NONE, 100L, 100L, 0));

        networkClientDelegate.poll(time.timer(0));
        assertTrue(fetcher.hasCompletedFetches());

        Map<TopicPartition, List<ConsumerRecord<byte[], byte[]>>> fetchedRecords = fetchRecords();
        assertTrue(fetchedRecords.containsKey(tp0));
        assertEquals(fetchedRecords.get(tp0).size(), 2);
    }
Supplies parameters to {@link #testHandleFetchResponseError(Errors, long, boolean, boolean)}.
clients/src/test/java/org/apache/kafka/clients/consumer/internals/FetchRequestManagerTest.java