Use RTCAudioSessionDelegate in AudioDeviceIOS.

webrtc/modules/audio_device/ios/objc/RTCAudioSessionTest.mm

 /*
  *  Copyright 2016 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>
 
 #include "testing/gtest/include/gtest/gtest.h"
 
 #import "webrtc/modules/audio_device/ios/objc/RTCAudioSession.h"
+#import "webrtc/modules/audio_device/ios/objc/RTCAudioSession+Private.h"
+
+@interface RTCAudioSessionTestDelegate : NSObject <RTCAudioSessionDelegate>
+@end
+
+@implementation RTCAudioSessionTestDelegate
+
+- (void)audioSessionDidBeginInterruption:(RTCAudioSession *)session {
+}
+
+- (void)audioSessionDidEndInterruption:(RTCAudioSession *)session
+                   shouldResumeSession:(BOOL)shouldResumeSession {
+}
+
+- (void)audioSessionDidChangeRoute:(RTCAudioSession *)session
+           reason:(AVAudioSessionRouteChangeReason)reason
+    previousRoute:(AVAudioSessionRouteDescription *)previousRoute {
+}
+
+- (void)audioSessionMediaServicesWereLost:(RTCAudioSession *)session {
+}
+
+- (void)audioSessionMediaServicesWereReset:(RTCAudioSession *)session {
+}
+
+- (void)audioSessionShouldConfigure:(RTCAudioSession *)session {
+}
+
+- (void)audioSessionShouldUnconfigure:(RTCAudioSession *)session {
+}
+
+@end
+
 
 @interface RTCAudioSessionTest : NSObject
 
 - (void)testLockForConfiguration;
 
 @end
 
 @implementation RTCAudioSessionTest
 
 - (void)testLockForConfiguration {
   RTCAudioSession *session = [RTCAudioSession sharedInstance];
 
   for (size_t i = 0; i < 2; i++) {
     [session lockForConfiguration];
     EXPECT_TRUE(session.isLocked);
   }
   for (size_t i = 0; i < 2; i++) {
     EXPECT_TRUE(session.isLocked);
     [session unlockForConfiguration];
   }
   EXPECT_FALSE(session.isLocked);
 }
 
+- (void)testAddAndRemoveDelegates {
+  RTCAudioSession *session = [RTCAudioSession sharedInstance];
+  NSMutableArray *delegates = [NSMutableArray array];
+  const size_t count = 5;
+  for (size_t i = 0; i < count; ++i) {
+    RTCAudioSessionTestDelegate *delegate =
+        [[RTCAudioSessionTestDelegate alloc] init];
+    [session addDelegate:delegate];
+    [delegates addObject:delegate];
+    EXPECT_EQ(i + 1, session.delegates.size());
+  }
+  [delegates enumerateObjectsUsingBlock:^(RTCAudioSessionTestDelegate *obj,
+                                          NSUInteger idx,
+                                          BOOL *stop) {
+    [session removeDelegate:obj];
+  }];
+  EXPECT_EQ(0u, session.delegates.size());
+}
+
+- (void)testPushDelegate {
+  RTCAudioSession *session = [RTCAudioSession sharedInstance];
+  NSMutableArray *delegates = [NSMutableArray array];
+  const size_t count = 2;
+  for (size_t i = 0; i < count; ++i) {
+    RTCAudioSessionTestDelegate *delegate =
+        [[RTCAudioSessionTestDelegate alloc] init];
+    [session addDelegate:delegate];
+    [delegates addObject:delegate];
+  }
+  // Test that it gets added to the front of the list.
+  RTCAudioSessionTestDelegate *pushedDelegate =
+      [[RTCAudioSessionTestDelegate alloc] init];
+  [session pushDelegate:pushedDelegate];
+  EXPECT_TRUE(pushedDelegate == session.delegates[0]);
+
+  // Test that it stays at the front of the list.
+  for (size_t i = 0; i < count; ++i) {
+    RTCAudioSessionTestDelegate *delegate =
+        [[RTCAudioSessionTestDelegate alloc] init];
+    [session addDelegate:delegate];
+    [delegates addObject:delegate];
+  }
+  EXPECT_TRUE(pushedDelegate == session.delegates[0]);
+
+  // Test that the next one goes to the front too.
+  pushedDelegate = [[RTCAudioSessionTestDelegate alloc] init];
+  [session pushDelegate:pushedDelegate];
+  EXPECT_TRUE(pushedDelegate == session.delegates[0]);
+}
+
+// Tests that delegates added to the audio session properly zero out. This is
+// checking an implementation detail (that vectors of __weak work as expected).
+- (void)testZeroingWeakDelegate {
+  RTCAudioSession *session = [RTCAudioSession sharedInstance];
+  @autoreleasepool {
+    // Add a delegate to the session. There should be one delegate at this
+    // point.
+    RTCAudioSessionTestDelegate *delegate =
+        [[RTCAudioSessionTestDelegate alloc] init];
+    [session addDelegate:delegate];
+    EXPECT_EQ(1u, session.delegates.size());
+    EXPECT_TRUE(session.delegates[0]);
+  }
+  // The previously created delegate should've de-alloced, leaving a nil ptr.
+  EXPECT_FALSE(session.delegates[0]);
+  RTCAudioSessionTestDelegate *delegate =
+      [[RTCAudioSessionTestDelegate alloc] init];
+  [session addDelegate:delegate];
+  // On adding a new delegate, nil ptrs should've been cleared.
+  EXPECT_EQ(1u, session.delegates.size());
+  EXPECT_TRUE(session.delegates[0]);
+}
+
 @end
 
-TEST(RTCAudioSessionTest, LockForConfiguration) {
+namespace webrtc {
+
+class AudioSessionTest : public ::testing::Test {
+ protected:
+  void TearDown() {
+    RTCAudioSession *session = [RTCAudioSession sharedInstance];
+    for (id<RTCAudioSessionDelegate> delegate : session.delegates) {
+      [session removeDelegate:delegate];
+    }
+  }
+};
+
+TEST_F(AudioSessionTest, LockForConfiguration) {
   RTCAudioSessionTest *test = [[RTCAudioSessionTest alloc] init];
   [test testLockForConfiguration];
 }
+
+TEST_F(AudioSessionTest, AddAndRemoveDelegates) {
+  RTCAudioSessionTest *test = [[RTCAudioSessionTest alloc] init];
+  [test testAddAndRemoveDelegates];
+}
+
+TEST_F(AudioSessionTest, PushDelegate) {
+  RTCAudioSessionTest *test = [[RTCAudioSessionTest alloc] init];
+  [test testPushDelegate];
+}
+
+TEST_F(AudioSessionTest, ZeroingWeakDelegate) {
+  RTCAudioSessionTest *test = [[RTCAudioSessionTest alloc] init];
+  [test testZeroingWeakDelegate];
+}
+
+}  // namespace webrtc