Add unit test class for RTCCameraVideoCapturer.

webrtc/sdk/objc/Framework/Classes/RTCCameraVideoCapturer.m

 /*
  *  Copyright 2017 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 <Foundation/Foundation.h>
 
 #import "WebRTC/RTCCameraVideoCapturer.h"
 #import "WebRTC/RTCLogging.h"
 
 #if TARGET_OS_IPHONE
 #import "WebRTC/UIDevice+RTCDevice.h"
 #endif
 
 #import "RTCDispatcher+Private.h"
 
 const int64_t kNanosecondsPerSecond = 1000000000;
 
 static inline BOOL IsMediaSubTypeSupported(FourCharCode mediaSubType) {
   return (mediaSubType == kCVPixelFormatType_420YpCbCr8PlanarFullRange ||
           mediaSubType == kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange);
 }
 
 @interface RTCCameraVideoCapturer ()<AVCaptureVideoDataOutputSampleBufferDelegate>
-@property(nonatomic, readonly) dispatch_queue_t frameQueue;
+@property(nonatomic, strong) AVCaptureVideoDataOutput *videoDataOutput;
+@property(nonatomic, strong) AVCaptureDevice *currentDevice;
+@property(nonatomic, strong) dispatch_queue_t frameQueue;
+@property(nonatomic, assign) RTCVideoRotation rotation;
+// Will the session be running once all asynchronous operations have been completed?
+@property(nonatomic, assign) BOOL willBeRunning;
+
 @end
 
 @implementation RTCCameraVideoCapturer {
-  AVCaptureVideoDataOutput *_videoDataOutput;
-  AVCaptureSession *_captureSession;
-  AVCaptureDevice *_currentDevice;
-  RTCVideoRotation _rotation;
   BOOL _hasRetriedOnFatalError;
   BOOL _isRunning;
-  // Will the session be running once all asynchronous operations have been completed?
-  BOOL _willBeRunning;
 }
 
+@synthesize captureSession = _captureSession;
+@synthesize currentDevice = _currentDevice;
 @synthesize frameQueue = _frameQueue;
-@synthesize captureSession = _captureSession;
+@synthesize rotation = _rotation;
+@synthesize videoDataOutput = _videoDataOutput;
+@synthesize willBeRunning = _willBeRunning;
 
 - (instancetype)initWithDelegate:(__weak id<RTCVideoCapturerDelegate>)delegate {
   if (self = [super initWithDelegate:delegate]) {
     // Create the capture session and all relevant inputs and outputs. We need
     // to do this in init because the application may want the capture session
     // before we start the capturer for e.g. AVCapturePreviewLayer. All objects
     // created here are retained until dealloc and never recreated.
     if (![self setupCaptureSession]) {
       return nil;
     }
@@ skipping 58 matching lines @@
 }
 
 - (void)startCaptureWithDevice:(AVCaptureDevice *)device
                         format:(AVCaptureDeviceFormat *)format
                            fps:(int)fps {
   _willBeRunning = true;
   [RTCDispatcher
       dispatchAsyncOnType:RTCDispatcherTypeCaptureSession
                     block:^{
                       RTCLogInfo("startCaptureWithDevice %@ @ %d fps", format, fps);
-
 #if TARGET_OS_IPHONE
                       [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
 #endif
-
-                      _currentDevice = device;
-
-                      NSError *error = nil;
-                      if ([_currentDevice lockForConfiguration:&error]) {
-                        [self updateDeviceCaptureFormat:format fps:fps];
-                      } else {
-                        RTCLogError(@"Failed to lock device %@. Error: %@", _currentDevice,
-                                    error.userInfo);
-                        return;
-                      }
-
-                      [self reconfigureCaptureSessionInput];
-                      [self updateOrientation];
-                      [_captureSession startRunning];
-
-                      [_currentDevice unlockForConfiguration];
-                      _isRunning = true;
+                      _isRunning = [self tryStartCaptureWithDevice:device format:format fps:fps];
                     }];
 }
 
 - (void)stopCapture {
   _willBeRunning = false;
   [RTCDispatcher
       dispatchAsyncOnType:RTCDispatcherTypeCaptureSession
                     block:^{
                       RTCLogInfo("Stop");
                       _currentDevice = nil;
@@ skipping 197 matching lines @@
     // TODO(denicija): Remove this color conversion and use the original capture format directly.
     kCVPixelBufferPixelFormatTypeKey : @(kCVPixelFormatType_420YpCbCr8BiPlanarFullRange)
   };
   videoDataOutput.alwaysDiscardsLateVideoFrames = NO;
   [videoDataOutput setSampleBufferDelegate:self queue:self.frameQueue];
   _videoDataOutput = videoDataOutput;
 }
 
 #pragma mark - Private, called inside capture queue
 
+- (BOOL)tryStartCaptureWithDevice:(AVCaptureDevice *)device
+                           format:(AVCaptureDeviceFormat *)format
+                              fps:(int)fps {
+  _currentDevice = device;
+
+  NSError *error = nil;
+  if ([_currentDevice lockForConfiguration:&error]) {
+    [self updateDeviceCaptureFormat:format fps:fps];
+  } else {
+    RTCLogError(@"Failed to lock device %@. Error: %@", _currentDevice, error.userInfo);
+    return NO;
+  }
+
+  [self reconfigureCaptureSessionInput];
+  [self updateOrientation];
+  [_captureSession startRunning];
+
+  [_currentDevice unlockForConfiguration];
+  return YES;
+}
+
 - (void)updateDeviceCaptureFormat:(AVCaptureDeviceFormat *)format fps:(int)fps {
   @try {
     _currentDevice.activeFormat = format;
     _currentDevice.activeVideoMinFrameDuration = CMTimeMake(1, fps);
   } @catch (NSException *exception) {
     RTCLogError(@"Failed to set active format!\n User info:%@", exception.userInfo);
     return;
   }
 }
 
@@ skipping 12 matching lines @@
   if ([_captureSession canAddInput:input]) {
     [_captureSession addInput:input];
   } else {
     RTCLogError(@"Cannot add camera as an input to the session.");
   }
   [_captureSession commitConfiguration];
 }
 
 - (void)updateOrientation {
 #if TARGET_OS_IPHONE
+  [self updateOrientation:[UIDevice currentDevice].orientation];
+#endif
+}
+
+#if TARGET_OS_IPHONE
+- (void)updateOrientation:(UIDeviceOrientation)orientation {
   BOOL usingFrontCamera = _currentDevice.position == AVCaptureDevicePositionFront;
-  switch ([UIDevice currentDevice].orientation) {
+  switch (orientation) {
     case UIDeviceOrientationPortrait:
       _rotation = RTCVideoRotation_90;
       break;
     case UIDeviceOrientationPortraitUpsideDown:
       _rotation = RTCVideoRotation_270;
       break;
     case UIDeviceOrientationLandscapeLeft:
       _rotation = usingFrontCamera ? RTCVideoRotation_180 : RTCVideoRotation_0;
       break;
     case UIDeviceOrientationLandscapeRight:
       _rotation = usingFrontCamera ? RTCVideoRotation_0 : RTCVideoRotation_180;
       break;
     case UIDeviceOrientationFaceUp:
     case UIDeviceOrientationFaceDown:
     case UIDeviceOrientationUnknown:
       // Ignore.
       break;
   }
+}
 #endif
-}
 
 @end