summaryrefslogtreecommitdiffstats
path: root/third_party/libwebrtc/sdk/objc/unittests/RTCAudioDeviceModule_xctest.mm
blob: f8ce844652a103a056c4ee2454cca2268064d509 (plain)
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
/*
 *  Copyright 2018 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#import <XCTest/XCTest.h>

#if defined(WEBRTC_IOS)
#import "sdk/objc/native/api/audio_device_module.h"
#endif

#include "api/scoped_refptr.h"

typedef int32_t(^NeedMorePlayDataBlock)(const size_t nSamples,
                                        const size_t nBytesPerSample,
                                        const size_t nChannels,
                                        const uint32_t samplesPerSec,
                                        void* audioSamples,
                                        size_t& nSamplesOut,
                                        int64_t* elapsed_time_ms,
                                        int64_t* ntp_time_ms);

typedef int32_t(^RecordedDataIsAvailableBlock)(const void* audioSamples,
                                               const size_t nSamples,
                                               const size_t nBytesPerSample,
                                               const size_t nChannels,
                                               const uint32_t samplesPerSec,
                                               const uint32_t totalDelayMS,
                                               const int32_t clockDrift,
                                               const uint32_t currentMicLevel,
                                               const bool keyPressed,
                                               uint32_t& newMicLevel);


// This class implements the AudioTransport API and forwards all methods to the appropriate blocks.
class MockAudioTransport : public webrtc::AudioTransport {
public:
  MockAudioTransport() {}
  ~MockAudioTransport() override {}

  void expectNeedMorePlayData(NeedMorePlayDataBlock block) {
    needMorePlayDataBlock = block;
  }

  void expectRecordedDataIsAvailable(RecordedDataIsAvailableBlock block) {
    recordedDataIsAvailableBlock = block;
  }

  int32_t NeedMorePlayData(const size_t nSamples,
                           const size_t nBytesPerSample,
                           const size_t nChannels,
                           const uint32_t samplesPerSec,
                           void* audioSamples,
                           size_t& nSamplesOut,
                           int64_t* elapsed_time_ms,
                           int64_t* ntp_time_ms) override {
    return needMorePlayDataBlock(nSamples,
                                 nBytesPerSample,
                                 nChannels,
                                 samplesPerSec,
                                 audioSamples,
                                 nSamplesOut,
                                 elapsed_time_ms,
                                 ntp_time_ms);
  }

  int32_t RecordedDataIsAvailable(const void* audioSamples,
                                  const size_t nSamples,
                                  const size_t nBytesPerSample,
                                  const size_t nChannels,
                                  const uint32_t samplesPerSec,
                                  const uint32_t totalDelayMS,
                                  const int32_t clockDrift,
                                  const uint32_t currentMicLevel,
                                  const bool keyPressed,
                                  uint32_t& newMicLevel) override {
    return recordedDataIsAvailableBlock(audioSamples,
                                        nSamples,
                                        nBytesPerSample,
                                        nChannels,
                                        samplesPerSec,
                                        totalDelayMS,
                                        clockDrift,
                                        currentMicLevel,
                                        keyPressed,
                                        newMicLevel);
  }

  void PullRenderData(int bits_per_sample,
                      int sample_rate,
                      size_t number_of_channels,
                      size_t number_of_frames,
                      void* audio_data,
                      int64_t* elapsed_time_ms,
                      int64_t* ntp_time_ms) override {}

 private:
  NeedMorePlayDataBlock needMorePlayDataBlock;
  RecordedDataIsAvailableBlock recordedDataIsAvailableBlock;
};

// Number of callbacks (input or output) the tests waits for before we set
// an event indicating that the test was OK.
static const NSUInteger kNumCallbacks = 10;
// Max amount of time we wait for an event to be set while counting callbacks.
static const NSTimeInterval kTestTimeOutInSec = 20.0;
// Number of bits per PCM audio sample.
static const NSUInteger kBitsPerSample = 16;
// Number of bytes per PCM audio sample.
static const NSUInteger kBytesPerSample = kBitsPerSample / 8;
// Average number of audio callbacks per second assuming 10ms packet size.
static const NSUInteger kNumCallbacksPerSecond = 100;
// Play out a test file during this time (unit is in seconds).
static const NSUInteger kFilePlayTimeInSec = 15;
// Run the full-duplex test during this time (unit is in seconds).
// Note that first `kNumIgnoreFirstCallbacks` are ignored.
static const NSUInteger kFullDuplexTimeInSec = 10;
// Wait for the callback sequence to stabilize by ignoring this amount of the
// initial callbacks (avoids initial FIFO access).
// Only used in the RunPlayoutAndRecordingInFullDuplex test.
static const NSUInteger kNumIgnoreFirstCallbacks = 50;

@interface RTCAudioDeviceModuleTests : XCTestCase {
  rtc::scoped_refptr<webrtc::AudioDeviceModule> audioDeviceModule;
  MockAudioTransport mock;
}

@property(nonatomic, assign) webrtc::AudioParameters playoutParameters;
@property(nonatomic, assign) webrtc::AudioParameters recordParameters;

@end

@implementation RTCAudioDeviceModuleTests

@synthesize playoutParameters;
@synthesize recordParameters;

- (void)setUp {
  [super setUp];
  audioDeviceModule = webrtc::CreateAudioDeviceModule();
  XCTAssertEqual(0, audioDeviceModule->Init());
  XCTAssertEqual(0, audioDeviceModule->GetPlayoutAudioParameters(&playoutParameters));
  XCTAssertEqual(0, audioDeviceModule->GetRecordAudioParameters(&recordParameters));
}

- (void)tearDown {
  XCTAssertEqual(0, audioDeviceModule->Terminate());
  audioDeviceModule = nullptr;
  [super tearDown];
}

- (void)startPlayout {
  XCTAssertFalse(audioDeviceModule->Playing());
  XCTAssertEqual(0, audioDeviceModule->InitPlayout());
  XCTAssertTrue(audioDeviceModule->PlayoutIsInitialized());
  XCTAssertEqual(0, audioDeviceModule->StartPlayout());
  XCTAssertTrue(audioDeviceModule->Playing());
}

- (void)stopPlayout {
  XCTAssertEqual(0, audioDeviceModule->StopPlayout());
  XCTAssertFalse(audioDeviceModule->Playing());
}

- (void)startRecording{
  XCTAssertFalse(audioDeviceModule->Recording());
  XCTAssertEqual(0, audioDeviceModule->InitRecording());
  XCTAssertTrue(audioDeviceModule->RecordingIsInitialized());
  XCTAssertEqual(0, audioDeviceModule->StartRecording());
  XCTAssertTrue(audioDeviceModule->Recording());
}

- (void)stopRecording{
  XCTAssertEqual(0, audioDeviceModule->StopRecording());
  XCTAssertFalse(audioDeviceModule->Recording());
}

- (NSURL*)fileURLForSampleRate:(int)sampleRate {
  XCTAssertTrue(sampleRate == 48000 || sampleRate == 44100 || sampleRate == 16000);
  NSString *filename = [NSString stringWithFormat:@"audio_short%d", sampleRate / 1000];
  NSURL *url = [[NSBundle mainBundle] URLForResource:filename withExtension:@"pcm"];
  XCTAssertNotNil(url);

  return url;
}

#pragma mark - Tests

- (void)testConstructDestruct {
  // Using the test fixture to create and destruct the audio device module.
}

- (void)testInitTerminate {
  // Initialization is part of the test fixture.
  XCTAssertTrue(audioDeviceModule->Initialized());
  XCTAssertEqual(0, audioDeviceModule->Terminate());
  XCTAssertFalse(audioDeviceModule->Initialized());
}

// Tests that playout can be initiated, started and stopped. No audio callback
// is registered in this test.
- (void)testStartStopPlayout {
  [self startPlayout];
  [self stopPlayout];
  [self startPlayout];
  [self stopPlayout];
}

// Tests that recording can be initiated, started and stopped. No audio callback
// is registered in this test.
- (void)testStartStopRecording {
  [self startRecording];
  [self stopRecording];
  [self startRecording];
  [self stopRecording];
}
// Verify that calling StopPlayout() will leave us in an uninitialized state
// which will require a new call to InitPlayout(). This test does not call
// StartPlayout() while being uninitialized since doing so will hit a
// RTC_DCHECK.
- (void)testStopPlayoutRequiresInitToRestart {
  XCTAssertEqual(0, audioDeviceModule->InitPlayout());
  XCTAssertEqual(0, audioDeviceModule->StartPlayout());
  XCTAssertEqual(0, audioDeviceModule->StopPlayout());
  XCTAssertFalse(audioDeviceModule->PlayoutIsInitialized());
}

// Verify that we can create two ADMs and start playing on the second ADM.
// Only the first active instance shall activate an audio session and the
// last active instance shall deactivate the audio session. The test does not
// explicitly verify correct audio session calls but instead focuses on
// ensuring that audio starts for both ADMs.
- (void)testStartPlayoutOnTwoInstances {
  // Create and initialize a second/extra ADM instance. The default ADM is
  // created by the test harness.
  rtc::scoped_refptr<webrtc::AudioDeviceModule> secondAudioDeviceModule =
      webrtc::CreateAudioDeviceModule();
  XCTAssertNotEqual(secondAudioDeviceModule.get(), nullptr);
  XCTAssertEqual(0, secondAudioDeviceModule->Init());

  // Start playout for the default ADM but don't wait here. Instead use the
  // upcoming second stream for that. We set the same expectation on number
  // of callbacks as for the second stream.
  mock.expectNeedMorePlayData(^int32_t(const size_t nSamples,
                                       const size_t nBytesPerSample,
                                       const size_t nChannels,
                                       const uint32_t samplesPerSec,
                                       void *audioSamples,
                                       size_t &nSamplesOut,
                                       int64_t *elapsed_time_ms,
                                       int64_t *ntp_time_ms) {
    nSamplesOut = nSamples;
    XCTAssertEqual(nSamples, self.playoutParameters.frames_per_10ms_buffer());
    XCTAssertEqual(nBytesPerSample, kBytesPerSample);
    XCTAssertEqual(nChannels, self.playoutParameters.channels());
    XCTAssertEqual((int)samplesPerSec, self.playoutParameters.sample_rate());
    XCTAssertNotEqual((void*)NULL, audioSamples);

    return 0;
  });

  XCTAssertEqual(0, audioDeviceModule->RegisterAudioCallback(&mock));
  [self startPlayout];

  // Initialize playout for the second ADM. If all is OK, the second ADM shall
  // reuse the audio session activated when the first ADM started playing.
  // This call will also ensure that we avoid a problem related to initializing
  // two different audio unit instances back to back (see webrtc:5166 for
  // details).
  XCTAssertEqual(0, secondAudioDeviceModule->InitPlayout());
  XCTAssertTrue(secondAudioDeviceModule->PlayoutIsInitialized());

  // Start playout for the second ADM and verify that it starts as intended.
  // Passing this test ensures that initialization of the second audio unit
  // has been done successfully and that there is no conflict with the already
  // playing first ADM.
  XCTestExpectation *playoutExpectation = [self expectationWithDescription:@"NeedMorePlayoutData"];
  __block int num_callbacks = 0;

  MockAudioTransport mock2;
  mock2.expectNeedMorePlayData(^int32_t(const size_t nSamples,
                                        const size_t nBytesPerSample,
                                        const size_t nChannels,
                                        const uint32_t samplesPerSec,
                                        void *audioSamples,
                                        size_t &nSamplesOut,
                                        int64_t *elapsed_time_ms,
                                        int64_t *ntp_time_ms) {
    nSamplesOut = nSamples;
    XCTAssertEqual(nSamples, self.playoutParameters.frames_per_10ms_buffer());
    XCTAssertEqual(nBytesPerSample, kBytesPerSample);
    XCTAssertEqual(nChannels, self.playoutParameters.channels());
    XCTAssertEqual((int)samplesPerSec, self.playoutParameters.sample_rate());
    XCTAssertNotEqual((void*)NULL, audioSamples);
    if (++num_callbacks == kNumCallbacks) {
      [playoutExpectation fulfill];
    }

    return 0;
  });

  XCTAssertEqual(0, secondAudioDeviceModule->RegisterAudioCallback(&mock2));
  XCTAssertEqual(0, secondAudioDeviceModule->StartPlayout());
  XCTAssertTrue(secondAudioDeviceModule->Playing());
  [self waitForExpectationsWithTimeout:kTestTimeOutInSec handler:nil];
  [self stopPlayout];
  XCTAssertEqual(0, secondAudioDeviceModule->StopPlayout());
  XCTAssertFalse(secondAudioDeviceModule->Playing());
  XCTAssertFalse(secondAudioDeviceModule->PlayoutIsInitialized());

  XCTAssertEqual(0, secondAudioDeviceModule->Terminate());
}

// Start playout and verify that the native audio layer starts asking for real
// audio samples to play out using the NeedMorePlayData callback.
- (void)testStartPlayoutVerifyCallbacks {

  XCTestExpectation *playoutExpectation = [self expectationWithDescription:@"NeedMorePlayoutData"];
  __block int num_callbacks = 0;
  mock.expectNeedMorePlayData(^int32_t(const size_t nSamples,
                                       const size_t nBytesPerSample,
                                       const size_t nChannels,
                                       const uint32_t samplesPerSec,
                                       void *audioSamples,
                                       size_t &nSamplesOut,
                                       int64_t *elapsed_time_ms,
                                       int64_t *ntp_time_ms) {
    nSamplesOut = nSamples;
    XCTAssertEqual(nSamples, self.playoutParameters.frames_per_10ms_buffer());
    XCTAssertEqual(nBytesPerSample, kBytesPerSample);
    XCTAssertEqual(nChannels, self.playoutParameters.channels());
    XCTAssertEqual((int)samplesPerSec, self.playoutParameters.sample_rate());
    XCTAssertNotEqual((void*)NULL, audioSamples);
    if (++num_callbacks == kNumCallbacks) {
      [playoutExpectation fulfill];
    }
    return 0;
  });

  XCTAssertEqual(0, audioDeviceModule->RegisterAudioCallback(&mock));

  [self startPlayout];
  [self waitForExpectationsWithTimeout:kTestTimeOutInSec handler:nil];
  [self stopPlayout];
}

// Start recording and verify that the native audio layer starts feeding real
// audio samples via the RecordedDataIsAvailable callback.
- (void)testStartRecordingVerifyCallbacks {
  XCTestExpectation *recordExpectation =
  [self expectationWithDescription:@"RecordedDataIsAvailable"];
  __block int num_callbacks = 0;

  mock.expectRecordedDataIsAvailable(^(const void* audioSamples,
                                       const size_t nSamples,
                                       const size_t nBytesPerSample,
                                       const size_t nChannels,
                                       const uint32_t samplesPerSec,
                                       const uint32_t totalDelayMS,
                                       const int32_t clockDrift,
                                       const uint32_t currentMicLevel,
                                       const bool keyPressed,
                                       uint32_t& newMicLevel) {
    XCTAssertNotEqual((void*)NULL, audioSamples);
    XCTAssertEqual(nSamples, self.recordParameters.frames_per_10ms_buffer());
    XCTAssertEqual(nBytesPerSample, kBytesPerSample);
    XCTAssertEqual(nChannels, self.recordParameters.channels());
    XCTAssertEqual((int)samplesPerSec, self.recordParameters.sample_rate());
    XCTAssertEqual(0, clockDrift);
    XCTAssertEqual(0u, currentMicLevel);
    XCTAssertFalse(keyPressed);
    if (++num_callbacks == kNumCallbacks) {
      [recordExpectation fulfill];
    }

    return 0;
  });

  XCTAssertEqual(0, audioDeviceModule->RegisterAudioCallback(&mock));
  [self startRecording];
  [self waitForExpectationsWithTimeout:kTestTimeOutInSec handler:nil];
  [self stopRecording];
}

// Start playout and recording (full-duplex audio) and verify that audio is
// active in both directions.
- (void)testStartPlayoutAndRecordingVerifyCallbacks {
  XCTestExpectation *playoutExpectation = [self expectationWithDescription:@"NeedMorePlayoutData"];
  __block NSUInteger callbackCount = 0;

  XCTestExpectation *recordExpectation =
  [self expectationWithDescription:@"RecordedDataIsAvailable"];
  recordExpectation.expectedFulfillmentCount = kNumCallbacks;

  mock.expectNeedMorePlayData(^int32_t(const size_t nSamples,
                                       const size_t nBytesPerSample,
                                       const size_t nChannels,
                                       const uint32_t samplesPerSec,
                                       void *audioSamples,
                                       size_t &nSamplesOut,
                                       int64_t *elapsed_time_ms,
                                       int64_t *ntp_time_ms) {
    nSamplesOut = nSamples;
    XCTAssertEqual(nSamples, self.playoutParameters.frames_per_10ms_buffer());
    XCTAssertEqual(nBytesPerSample, kBytesPerSample);
    XCTAssertEqual(nChannels, self.playoutParameters.channels());
    XCTAssertEqual((int)samplesPerSec, self.playoutParameters.sample_rate());
    XCTAssertNotEqual((void*)NULL, audioSamples);
    if (callbackCount++ >= kNumCallbacks) {
      [playoutExpectation fulfill];
    }

    return 0;
  });

  mock.expectRecordedDataIsAvailable(^(const void* audioSamples,
                                       const size_t nSamples,
                                       const size_t nBytesPerSample,
                                       const size_t nChannels,
                                       const uint32_t samplesPerSec,
                                       const uint32_t totalDelayMS,
                                       const int32_t clockDrift,
                                       const uint32_t currentMicLevel,
                                       const bool keyPressed,
                                       uint32_t& newMicLevel) {
    XCTAssertNotEqual((void*)NULL, audioSamples);
    XCTAssertEqual(nSamples, self.recordParameters.frames_per_10ms_buffer());
    XCTAssertEqual(nBytesPerSample, kBytesPerSample);
    XCTAssertEqual(nChannels, self.recordParameters.channels());
    XCTAssertEqual((int)samplesPerSec, self.recordParameters.sample_rate());
    XCTAssertEqual(0, clockDrift);
    XCTAssertEqual(0u, currentMicLevel);
    XCTAssertFalse(keyPressed);
    [recordExpectation fulfill];

    return 0;
  });

  XCTAssertEqual(0, audioDeviceModule->RegisterAudioCallback(&mock));
  [self startPlayout];
  [self startRecording];
  [self waitForExpectationsWithTimeout:kTestTimeOutInSec handler:nil];
  [self stopRecording];
  [self stopPlayout];
}

// Start playout and read audio from an external PCM file when the audio layer
// asks for data to play out. Real audio is played out in this test but it does
// not contain any explicit verification that the audio quality is perfect.
- (void)testRunPlayoutWithFileAsSource {
  XCTAssertEqual(1u, playoutParameters.channels());

  // Using XCTestExpectation to count callbacks is very slow.
  XCTestExpectation *playoutExpectation = [self expectationWithDescription:@"NeedMorePlayoutData"];
  const int expectedCallbackCount = kFilePlayTimeInSec * kNumCallbacksPerSecond;
  __block int callbackCount = 0;

  NSURL *fileURL = [self fileURLForSampleRate:playoutParameters.sample_rate()];
  NSInputStream *inputStream = [[NSInputStream alloc] initWithURL:fileURL];

  mock.expectNeedMorePlayData(^int32_t(const size_t nSamples,
                                       const size_t nBytesPerSample,
                                       const size_t nChannels,
                                       const uint32_t samplesPerSec,
                                       void *audioSamples,
                                       size_t &nSamplesOut,
                                       int64_t *elapsed_time_ms,
                                       int64_t *ntp_time_ms) {
    [inputStream read:(uint8_t *)audioSamples maxLength:nSamples*nBytesPerSample*nChannels];
    nSamplesOut = nSamples;
    if (callbackCount++ == expectedCallbackCount) {
      [playoutExpectation fulfill];
    }

    return 0;
  });

  XCTAssertEqual(0, audioDeviceModule->RegisterAudioCallback(&mock));
  [self startPlayout];
  NSTimeInterval waitTimeout = kFilePlayTimeInSec * 2.0;
  [self waitForExpectationsWithTimeout:waitTimeout handler:nil];
  [self stopPlayout];
}

- (void)testDevices {
  // Device enumeration is not supported. Verify fixed values only.
  XCTAssertEqual(1, audioDeviceModule->PlayoutDevices());
  XCTAssertEqual(1, audioDeviceModule->RecordingDevices());
}

// Start playout and recording and store recorded data in an intermediate FIFO
// buffer from which the playout side then reads its samples in the same order
// as they were stored. Under ideal circumstances, a callback sequence would
// look like: ...+-+-+-+-+-+-+-..., where '+' means 'packet recorded' and '-'
// means 'packet played'. Under such conditions, the FIFO would only contain
// one packet on average. However, under more realistic conditions, the size
// of the FIFO will vary more due to an unbalance between the two sides.
// This test tries to verify that the device maintains a balanced callback-
// sequence by running in loopback for ten seconds while measuring the size
// (max and average) of the FIFO. The size of the FIFO is increased by the
// recording side and decreased by the playout side.
// TODO(henrika): tune the final test parameters after running tests on several
// different devices.
- (void)testRunPlayoutAndRecordingInFullDuplex {
  XCTAssertEqual(recordParameters.channels(), playoutParameters.channels());
  XCTAssertEqual(recordParameters.sample_rate(), playoutParameters.sample_rate());

  XCTestExpectation *playoutExpectation = [self expectationWithDescription:@"NeedMorePlayoutData"];
  __block NSUInteger playoutCallbacks = 0;
  NSUInteger expectedPlayoutCallbacks = kFullDuplexTimeInSec * kNumCallbacksPerSecond;

  // FIFO queue and measurements
  NSMutableArray *fifoBuffer = [NSMutableArray arrayWithCapacity:20];
  __block NSUInteger fifoMaxSize = 0;
  __block NSUInteger fifoTotalWrittenElements = 0;
  __block NSUInteger fifoWriteCount = 0;

  mock.expectRecordedDataIsAvailable(^(const void* audioSamples,
                                       const size_t nSamples,
                                       const size_t nBytesPerSample,
                                       const size_t nChannels,
                                       const uint32_t samplesPerSec,
                                       const uint32_t totalDelayMS,
                                       const int32_t clockDrift,
                                       const uint32_t currentMicLevel,
                                       const bool keyPressed,
                                       uint32_t& newMicLevel) {
    if (fifoWriteCount++ < kNumIgnoreFirstCallbacks) {
      return 0;
    }

    NSData *data = [NSData dataWithBytes:audioSamples length:nSamples*nBytesPerSample*nChannels];
    @synchronized(fifoBuffer) {
      [fifoBuffer addObject:data];
      fifoMaxSize = MAX(fifoMaxSize, fifoBuffer.count);
      fifoTotalWrittenElements += fifoBuffer.count;
    }

    return 0;
  });

  mock.expectNeedMorePlayData(^int32_t(const size_t nSamples,
                                       const size_t nBytesPerSample,
                                       const size_t nChannels,
                                       const uint32_t samplesPerSec,
                                       void *audioSamples,
                                       size_t &nSamplesOut,
                                       int64_t *elapsed_time_ms,
                                       int64_t *ntp_time_ms) {
    nSamplesOut = nSamples;
    NSData *data;
    @synchronized(fifoBuffer) {
      data = fifoBuffer.firstObject;
      if (data) {
        [fifoBuffer removeObjectAtIndex:0];
      }
    }

    if (data) {
      memcpy(audioSamples, (char*) data.bytes, data.length);
    } else {
      memset(audioSamples, 0, nSamples*nBytesPerSample*nChannels);
    }

    if (playoutCallbacks++ == expectedPlayoutCallbacks) {
      [playoutExpectation fulfill];
    }
    return 0;
  });

  XCTAssertEqual(0, audioDeviceModule->RegisterAudioCallback(&mock));
  [self startRecording];
  [self startPlayout];
  NSTimeInterval waitTimeout = kFullDuplexTimeInSec * 2.0;
  [self waitForExpectationsWithTimeout:waitTimeout handler:nil];

  size_t fifoAverageSize =
      (fifoTotalWrittenElements == 0)
        ? 0.0
        : 0.5 + (double)fifoTotalWrittenElements / (fifoWriteCount - kNumIgnoreFirstCallbacks);

  [self stopPlayout];
  [self stopRecording];
  XCTAssertLessThan(fifoAverageSize, 10u);
  XCTAssertLessThan(fifoMaxSize, 20u);
}

@end