forked from confluentinc/confluent-kafka-python
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathtest_AIOProducer.py
More file actions
646 lines (500 loc) · 26.4 KB
/
test_AIOProducer.py
File metadata and controls
646 lines (500 loc) · 26.4 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Unit tests for AIOProducer class.
"""
import asyncio
import concurrent.futures
from unittest.mock import Mock, patch
import pytest
from confluent_kafka import KafkaError, KafkaException
from confluent_kafka.aio.producer._AIOProducer import AIOProducer
class TestAIOProducer:
"""Unit tests for AIOProducer class."""
@pytest.fixture
def mock_producer(self):
with patch('confluent_kafka.aio.producer._AIOProducer.confluent_kafka.Producer') as mock:
yield mock
@pytest.fixture
def mock_common(self):
with patch('confluent_kafka.aio.producer._AIOProducer._common') as mock:
async def mock_async_call(executor, blocking_task, *args, **kwargs):
return blocking_task(*args, **kwargs)
mock.async_call.side_effect = mock_async_call
yield mock
@pytest.fixture
def basic_config(self):
return {'bootstrap.servers': 'localhost:9092'}
@pytest.mark.asyncio
async def test_constructor_behavior(self, mock_producer, mock_common, basic_config):
custom_executor = concurrent.futures.ThreadPoolExecutor(max_workers=5)
try:
producer1 = AIOProducer(basic_config, max_workers=3, executor=custom_executor)
assert producer1.executor is custom_executor
assert producer1.executor._max_workers == 5
assert producer1._is_closed is False
assert hasattr(producer1, '_buffer_timeout_manager')
assert hasattr(producer1, '_producer')
producer2 = AIOProducer(basic_config, max_workers=2, batch_size=500)
assert producer2.executor is not custom_executor
assert isinstance(producer2.executor, concurrent.futures.ThreadPoolExecutor)
assert producer2.executor._max_workers == 2
assert producer2._batch_size == 500
assert producer2._is_closed is False
assert hasattr(producer2, '_buffer_timeout_manager')
await producer2.close()
assert producer2._is_closed is True
finally:
custom_executor.shutdown(wait=True)
@pytest.mark.asyncio
async def test_close_method(self, mock_producer, mock_common, basic_config):
producer = AIOProducer(basic_config)
assert producer._is_closed is False
await producer.close()
assert producer._is_closed is True
producer2 = AIOProducer(basic_config)
assert producer2._is_closed is False
await producer2.close()
await producer2.close()
assert producer2._is_closed is True
@pytest.mark.asyncio
async def test_async_context_manager(self, mock_producer, mock_common, basic_config):
async with AIOProducer(basic_config) as producer:
assert producer._is_closed is False
assert producer._is_closed is True
async with AIOProducer(basic_config) as producer2:
assert producer2._is_closed is False
await producer2.close()
await producer2.close()
assert producer2._is_closed is True
@pytest.mark.asyncio
async def test_call_method_executor_usage(self, mock_producer, mock_common, basic_config):
producer = AIOProducer(basic_config)
mock_method = Mock(return_value="test_result")
result = await producer._call(mock_method, "arg1", kwarg1="value1")
mock_method.assert_called_once_with("arg1", kwarg1="value1")
assert result == "test_result"
@pytest.mark.asyncio
async def test_produce_success(self, mock_producer, mock_common, basic_config):
producer = AIOProducer(basic_config, batch_size=1)
mock_msg = Mock()
async def mock_flush_buffer(target_topic=None):
batches = producer._batch_processor.create_batches(target_topic)
for batch in batches:
for future in batch.futures:
if not future.done():
future.set_result(mock_msg)
producer._batch_processor.clear_buffer()
with patch.object(producer, '_flush_buffer', side_effect=mock_flush_buffer):
result_future = await producer.produce(topic="test_topic", value="test_value")
result = await result_future
assert result is mock_msg
await producer.close()
@pytest.mark.asyncio
async def test_produce_error(self, mock_producer, mock_common, basic_config):
producer = AIOProducer(basic_config, batch_size=1)
mock_error = KafkaError(KafkaError._MSG_TIMED_OUT)
async def mock_flush_buffer(target_topic=None):
batches = producer._batch_processor.create_batches(target_topic)
for batch in batches:
for future in batch.futures:
if not future.done():
future.set_exception(KafkaException(mock_error))
producer._batch_processor.clear_buffer()
with patch.object(producer, '_flush_buffer', side_effect=mock_flush_buffer):
result_future = await producer.produce(topic="test_topic", value="test_value")
with pytest.raises(KafkaException):
await result_future
await producer.close()
@pytest.mark.asyncio
async def test_produce_with_delayed_callback(self, mock_producer, mock_common, basic_config):
"""Test that Future properly waits for delayed delivery callback with batching."""
producer = AIOProducer(basic_config, batch_size=2) # Need 2 messages to trigger flush
batch_called = asyncio.Event()
captured_messages = None
def mock_produce_batch(topic, messages, partition=None):
nonlocal captured_messages
captured_messages = messages
batch_called.set()
# Don't call callbacks immediately - simulate real async behavior
mock_producer.return_value.produce_batch.side_effect = mock_produce_batch
mock_producer.return_value.poll.return_value = 1
# Start first produce - won't trigger flush yet, but will return a Future
first_future = await producer.produce(topic="test", value="test1")
# The Future should be pending (not resolved yet)
assert not first_future.done()
# Add second message to trigger batch flush
await producer.produce(topic="test", value="test2")
# Wait for the batch operation to be called
await asyncio.wait_for(batch_called.wait(), timeout=2.0)
# Batch was called and should have captured messages with callbacks
assert captured_messages is not None
assert len(captured_messages) == 2
assert not first_future.done()
# Simulate delayed delivery callback (like from background polling)
mock_msg = Mock()
mock_msg.topic.return_value = "test"
mock_msg.value.return_value = b"test1"
# Call callback for first message (index 0)
first_callback = captured_messages[0]['callback']
first_callback(None, mock_msg)
# Now the Future should resolve
result = await first_future
assert result == mock_msg
await producer.close()
@pytest.mark.asyncio
async def test_buffer_timeout_background_task(self, mock_producer, mock_common, basic_config):
"""Test that buffer timeout task runs continuously in the background."""
# Create producer with short timeout for testing
producer = AIOProducer(basic_config, buffer_timeout=0.1)
# Test that timeout task is created and running
assert producer._buffer_timeout_manager._timeout_task is not None
assert not producer._buffer_timeout_manager._timeout_task.done()
assert producer._is_closed is False
# Wait a bit to ensure task is running
await asyncio.sleep(0.05)
assert not producer._buffer_timeout_manager._timeout_task.done()
# Close the producer
await producer.close()
# Verify task stops and producer is closed
assert producer._is_closed is True
await asyncio.sleep(0.1) # Grace period for cleanup
assert (
producer._buffer_timeout_manager._timeout_task is None
or producer._buffer_timeout_manager._timeout_task.done()
)
@pytest.mark.asyncio
async def test_multiple_concurrent_produce(self, mock_producer, mock_common, basic_config):
"""Test multiple concurrent produce operations with batching."""
producer = AIOProducer(basic_config, max_workers=3, batch_size=1) # Force immediate flush
completed_produces = []
batch_call_count = 0
def mock_produce_batch(topic, messages, partition=None):
nonlocal batch_call_count
batch_call_count += 1
# Simulate successful delivery for each message in batch
for i, msg_data in enumerate(messages):
mock_msg = Mock()
mock_msg.topic.return_value = topic
mock_msg.value.return_value = (
msg_data['value'].encode() if isinstance(msg_data['value'], str) else msg_data['value']
)
completed_produces.append((topic, msg_data['value']))
# Call the individual message callback
if 'callback' in msg_data:
msg_data['callback'](None, mock_msg)
mock_producer.return_value.produce_batch.side_effect = mock_produce_batch
mock_producer.return_value.poll.return_value = 1
# Start multiple produce operations concurrently
tasks = [asyncio.create_task(producer.produce(topic="test", value=f"msg{i}")) for i in range(3)]
# All tasks should complete successfully (tests real concurrency)
results = await asyncio.gather(*tasks)
# Verify all operations completed
assert len(results) == 3
assert all(result is not None for result in results)
assert batch_call_count == 3 # Each message triggers its own batch due to batch_size=1
assert len(completed_produces) == 3
# Verify all messages were produced
produced_values = [value for topic, value in completed_produces]
expected_values = ["msg0", "msg1", "msg2"]
assert sorted(produced_values) == sorted(expected_values)
await producer.close()
@pytest.mark.asyncio
async def test_constructor_new_implementation(self, mock_producer, mock_common, basic_config):
producer1 = AIOProducer(basic_config)
assert producer1._batch_size == 1000
assert isinstance(producer1.executor, concurrent.futures.ThreadPoolExecutor)
assert hasattr(producer1, '_loop')
assert hasattr(producer1, '_buffer_timeout_manager')
assert producer1._batch_processor.is_buffer_empty()
assert producer1._is_closed is False
await producer1.close()
custom_executor = concurrent.futures.ThreadPoolExecutor(max_workers=8)
try:
producer2 = AIOProducer(basic_config, executor=custom_executor, batch_size=500, buffer_timeout=10.0)
assert producer2.executor is custom_executor
assert producer2._batch_size == 500
assert hasattr(producer2, '_buffer_timeout_manager')
await producer2.close()
finally:
custom_executor.shutdown(wait=True)
@pytest.mark.asyncio
async def test_lifecycle_management_new_implementation(self, mock_producer, mock_common, basic_config):
"""Test lifecycle management for current implementation."""
# Test close method with messages in buffer
producer = AIOProducer(basic_config)
# Add some messages to buffer
with patch.object(producer, '_flush_buffer'):
await producer.produce('test', 'msg1')
assert producer._batch_processor.get_buffer_size() == 1
# Test close method
await producer.close()
assert producer._is_closed is True
assert (
producer._buffer_timeout_manager._timeout_task is None
or producer._buffer_timeout_manager._timeout_task.done()
)
@pytest.mark.asyncio
async def test_buffer_timeout_task_management(self, mock_producer, mock_common, basic_config):
"""Test timeout task lifecycle and weak references."""
# Test task creation and configuration
producer = AIOProducer(basic_config, buffer_timeout=1.0)
assert producer._buffer_timeout_manager._timeout_task is not None
assert not producer._buffer_timeout_manager._timeout_task.done()
assert producer._buffer_timeout_manager._timeout == 1.0
assert producer._is_closed is False
# Test task stops on close
await producer.close()
assert producer._is_closed is True
assert (
producer._buffer_timeout_manager._timeout_task is None
or producer._buffer_timeout_manager._timeout_task.done()
)
@pytest.mark.asyncio
async def test_buffer_timeout_behavior(self, mock_producer, mock_common, basic_config):
"""Test buffer activity tracking and timeout triggers."""
# Test buffer activity tracking
producer = AIOProducer(basic_config)
initial_time = producer._buffer_timeout_manager._last_activity
assert initial_time > 0
# Activity updates on produce
await asyncio.sleep(0.01) # Ensure time difference
with patch.object(producer, '_flush_buffer'): # Prevent auto-flush
await producer.produce('test', 'msg1')
assert producer._buffer_timeout_manager._last_activity > initial_time
await producer.close()
@pytest.mark.asyncio
async def test_poll_method_new_implementation(self, mock_producer, mock_common, basic_config):
"""Test poll method with different timeout scenarios."""
producer = AIOProducer(basic_config)
# Test timeout=0 (non-blocking)
with patch.object(producer, '_call') as mock_call:
await producer.poll(timeout=0)
mock_call.assert_called_with(producer._producer.poll, 0)
# Test positive timeout (blocking via ThreadPool)
with patch.object(producer, '_call') as mock_call:
await producer.poll(timeout=5)
mock_call.assert_called_with(producer._producer.poll, 5)
await producer.close()
@pytest.mark.asyncio
async def test_produce_method_batching(self, mock_producer, mock_common, basic_config):
"""Test produce method with batching behavior."""
producer = AIOProducer(basic_config, batch_size=3)
# Test basic produce adds to buffer
with patch.object(producer, '_flush_buffer') as mock_flush:
future1 = await producer.produce('topic1', 'value1', key='key1')
assert producer._batch_processor.get_buffer_size() == 1
assert len(producer._batch_processor._buffer_futures) == 1
assert isinstance(future1, asyncio.Future)
mock_flush.assert_not_called() # Should not flush yet
# Test batch size trigger (3rd message should trigger flush)
with patch.object(producer, '_flush_buffer') as mock_flush:
await producer.produce('topic1', 'value2') # 2nd message
await producer.produce('topic1', 'value3') # 3rd message - should trigger flush
mock_flush.assert_called()
await producer.close()
@pytest.mark.asyncio
async def test_flush_and_purge_methods_new_implementation(self, mock_producer, mock_common, basic_config):
"""Test flush and purge methods for current implementation."""
producer = AIOProducer(basic_config)
# Add messages to buffer
with patch.object(producer, '_flush_buffer'): # Prevent auto-flush
await producer.produce('test', 'msg1')
await producer.produce('test', 'msg2')
assert producer._batch_processor.get_buffer_size() == 2
# Test purge clears buffers
with patch.object(producer, '_call') as mock_call:
await producer.purge()
mock_call.assert_called_with(producer._producer.purge)
assert producer._batch_processor.get_buffer_size() == 0
assert len(producer._batch_processor._buffer_futures) == 0
await producer.close()
@pytest.mark.asyncio
async def test_group_messages_by_topic(self, mock_producer, mock_common, basic_config):
"""Test message grouping by topic for batch processing."""
producer = AIOProducer(basic_config)
# Test empty buffer
groups = producer._batch_processor._group_messages_by_topic_and_partition()
assert groups == {}
# Add mixed topic messages
producer._batch_processor._message_buffer = [
{'topic': 'topic1', 'value': 'msg1', 'user_callback': None},
{'topic': 'topic2', 'value': 'msg2', 'user_callback': Mock()},
{'topic': 'topic1', 'value': 'msg3', 'user_callback': None},
]
producer._batch_processor._buffer_futures = [Mock(), Mock(), Mock()]
groups = producer._batch_processor._group_messages_by_topic_and_partition()
# Test grouping correctness
assert len(groups) == 2
assert ('topic1', -1) in groups and ('topic2', -1) in groups
assert len(groups[('topic1', -1)]['messages']) == 2 # msg1, msg3
assert len(groups[('topic2', -1)]['messages']) == 1 # msg2
await producer.close()
@pytest.mark.asyncio
async def test_error_handling_new_implementation(self, mock_producer, mock_common, basic_config):
"""Test error handling in current implementation."""
producer = AIOProducer(basic_config)
# Test batch error propagation
producer._batch_processor._message_buffer = [{'topic': 'test', 'value': 'msg', 'user_callback': None}]
producer._batch_processor._buffer_futures = [asyncio.Future()]
with patch.object(producer._batch_processor, 'flush_buffer', side_effect=Exception("Batch failed")):
with pytest.raises(Exception, match="Batch failed"):
await producer._flush_buffer()
await producer.close()
@pytest.mark.asyncio
async def test_future_based_usage_pattern(self, mock_producer, mock_common, basic_config):
"""Test the recommended Future-based usage pattern instead of callbacks."""
producer = AIOProducer(basic_config, batch_size=1)
# Mock successful delivery
mock_msg = Mock()
mock_msg.topic.return_value = "test-topic"
mock_msg.value.return_value = b"test-value"
async def mock_flush_buffer(target_topic=None):
batches = producer._batch_processor.create_batches(target_topic)
for batch in batches:
for future in batch.futures:
if not future.done():
future.set_result(mock_msg)
producer._batch_processor.clear_buffer()
with patch.object(producer, '_flush_buffer', side_effect=mock_flush_buffer):
# Recommended usage: await the Future returned by produce()
future = await producer.produce(topic="test-topic", value="test-value")
result = await future
# Verify the result
assert result is mock_msg
assert result.topic() == "test-topic"
assert result.value() == b"test-value"
await producer.close()
@pytest.mark.asyncio
async def test_future_based_error_handling(self, mock_producer, mock_common, basic_config):
"""Test Future-based error handling pattern."""
producer = AIOProducer(basic_config, batch_size=1)
# Mock delivery error
mock_error = KafkaException(KafkaError(KafkaError._MSG_TIMED_OUT))
async def mock_flush_buffer(target_topic=None):
batches = producer._batch_processor.create_batches(target_topic)
for batch in batches:
for future in batch.futures:
if not future.done():
future.set_exception(mock_error)
producer._batch_processor.clear_buffer()
with patch.object(producer, '_flush_buffer', side_effect=mock_flush_buffer):
# Recommended usage: handle exceptions via Future
future = await producer.produce(topic="test-topic", value="test-value")
with pytest.raises(KafkaException):
await future
await producer.close()
@pytest.mark.asyncio
async def test_future_based_concurrent_usage(self, mock_producer, mock_common, basic_config):
"""Test Future-based concurrent usage pattern."""
producer = AIOProducer(basic_config, batch_size=1)
# Mock successful delivery
mock_msg = Mock()
mock_msg.topic.return_value = "test-topic"
mock_msg.value.return_value = b"test-value"
async def mock_flush_buffer(target_topic=None):
batches = producer._batch_processor.create_batches(target_topic)
for batch in batches:
for future in batch.futures:
if not future.done():
future.set_result(mock_msg)
producer._batch_processor.clear_buffer()
with patch.object(producer, '_flush_buffer', side_effect=mock_flush_buffer):
# Recommended usage: collect Futures and await them together
futures = []
for i in range(5):
future = await producer.produce(topic="test-topic", value=f"test-value-{i}")
futures.append(future)
# Wait for all deliveries to complete
results = await asyncio.gather(*futures)
# Verify all results
assert len(results) == 5
for result in results:
assert result is mock_msg
await producer.close()
@pytest.mark.asyncio
async def test_edge_cases_batching(self, mock_producer, mock_common, basic_config):
"""Test edge cases in batching behavior."""
producer = AIOProducer(basic_config, batch_size=100)
# Test large batch handling
with patch.object(producer, '_flush_buffer') as mock_flush:
large_batch_tasks = [producer.produce('test', f'msg{i}') for i in range(150)] # Exceeds batch_size
# Should trigger flush automatically at 100
await asyncio.gather(*large_batch_tasks)
assert mock_flush.call_count >= 1 # At least one flush
await producer.close()
@pytest.mark.asyncio
async def test_aio_producer_len_with_buffered_messages(self, mock_producer, mock_common, basic_config):
"""Test that __len__ counts messages in async batch buffer"""
producer = AIOProducer(basic_config, batch_size=10, buffer_timeout=0)
# Produce 5 messages (less than batch_size, so they stay in buffer)
with patch.object(producer, '_flush_buffer') as mock_flush: # Prevent auto-flush
for i in range(5):
await producer.produce('test-topic', value=f'msg-{i}'.encode())
# Verify flush was not called (messages stayed in buffer)
mock_flush.assert_not_called()
# len() should count messages in buffer
assert len(producer) == 5
assert producer._batch_processor.get_buffer_size() == 5
assert len(producer._producer) == 0 # Nothing in librdkafka yet
# Verify len() equals the sum
assert len(producer) == producer._batch_processor.get_buffer_size() + len(producer._producer)
await producer.close()
@pytest.mark.asyncio
async def test_aio_producer_len_after_flush(self, mock_producer, mock_common, basic_config):
"""Test that __len__ counts messages after flush to librdkafka"""
producer = AIOProducer(basic_config, batch_size=10, buffer_timeout=0)
# Produce and flush
with patch.object(producer, '_flush_buffer'): # Prevent auto-flush
for i in range(5):
await producer.produce('test-topic', value=f'msg-{i}'.encode())
# Flush to move messages to librdkafka
await producer.flush()
# After flush, messages move to librdkafka queue
# Verify len() correctly equals the sum of buffer + librdkafka
buffer_count = producer._batch_processor.get_buffer_size()
librdkafka_count = len(producer._producer)
total_len = len(producer)
# Buffer should be empty after flush
assert buffer_count == 0
# Verify len() equals the sum (this validates the __len__ implementation)
assert total_len == buffer_count + librdkafka_count
# Messages should be in librdkafka queue after flush
assert total_len == librdkafka_count
await producer.close()
@pytest.mark.asyncio
async def test_aio_producer_len_closed_producer(self, mock_producer, mock_common, basic_config):
"""Test that __len__ returns 0 for closed producer"""
producer = AIOProducer(basic_config, batch_size=10, buffer_timeout=0)
# Produce some messages
with patch.object(producer, '_flush_buffer'): # Prevent auto-flush
for i in range(3):
await producer.produce('test-topic', value=f'msg-{i}'.encode())
# Verify messages are there
assert len(producer) == 3
# Close producer
await producer.close()
# len() should return 0 for closed producer
assert len(producer) == 0
@pytest.mark.asyncio
async def test_aio_producer_len_mixed_state(self, mock_producer, mock_common, basic_config):
"""Test __len__ when messages are in both buffer and librdkafka queue"""
producer = AIOProducer(basic_config, batch_size=5, buffer_timeout=0)
# Produce 7 messages - first 5 should flush (batch_size=5), last 2 stay in buffer
with patch.object(producer, '_flush_buffer') as mock_flush:
for i in range(7):
await producer.produce('test-topic', value=f'msg-{i}'.encode())
# With batch_size=5, flush should be called after 5th message
# Verify flush was called (at least once when batch_size reached)
assert mock_flush.call_count >= 1
# After batch_size messages, some may have flushed
# Total should be sum of buffer + librdkafka queue
buffer_count = producer._batch_processor.get_buffer_size()
librdkafka_count = len(producer._producer)
total_count = len(producer)
# Verify len() correctly equals the sum (this validates the __len__ implementation)
assert total_count == buffer_count + librdkafka_count
# At least the messages beyond batch_size should be in buffer
# (exact count depends on flush behavior)
assert total_count >= 2 # At least the last 2 should be pending
await producer.close()