Fixes audio renderer adapter

Sources/LiveKit/Audio/Manager/AudioManager.swift

@@ -101,10 +101,10 @@
         // Keep this var within State so it's protected by UnfairLock
         public var localTracksCount: Int = 0
         public var remoteTracksCount: Int = 0
         public var customConfigureFunc: ConfigureAudioSessionFunc?
         public var sessionConfiguration: AudioSessionConfiguration?
 
         public var trackState: TrackState {
             switch (localTracksCount > 0, remoteTracksCount > 0) {
             case (true, false): .localOnly
             case (false, true): .remoteOnly
@@ -117,9 +117,17 @@
 
     // MARK: - AudioProcessingModule
 
-    private lazy var capturePostProcessingDelegateAdapter = AudioCustomProcessingDelegateAdapter(label: "capturePost")
-
-    private lazy var renderPreProcessingDelegateAdapter = AudioCustomProcessingDelegateAdapter(label: "renderPre")
+    private lazy var capturePostProcessingDelegateAdapter = AudioCustomProcessingDelegateAdapter(
+        label: "capturePost",
+        rtcDelegateGetter: { RTC.audioProcessingModule.capturePostProcessingDelegate },
+        rtcDelegateSetter: { RTC.audioProcessingModule.capturePostProcessingDelegate = $0 }
+    )
+
+    private lazy var renderPreProcessingDelegateAdapter = AudioCustomProcessingDelegateAdapter(
+        label: "renderPre",
+        rtcDelegateGetter: { RTC.audioProcessingModule.renderPreProcessingDelegate },
+        rtcDelegateSetter: { RTC.audioProcessingModule.renderPreProcessingDelegate = $0 }
+    )
 
     let capturePostProcessingDelegateSubject = CurrentValueSubject<AudioCustomProcessingDelegate?, Never>(nil)
 
@@ -128,15 +136,7 @@
     /// - Note: If you only need to observe the buffer (rather than modify it), use ``add(localAudioRenderer:)`` instead
     public var capturePostProcessingDelegate: AudioCustomProcessingDelegate? {
         didSet {
-            if let capturePostProcessingDelegate {
-                // Clear WebRTC delegate first - this triggers audioProcessingRelease() on the old target
-                RTC.audioProcessingModule.capturePostProcessingDelegate = nil
-                capturePostProcessingDelegateAdapter.set(target: capturePostProcessingDelegate)
-                RTC.audioProcessingModule.capturePostProcessingDelegate = capturePostProcessingDelegateAdapter
-            } else {
-                RTC.audioProcessingModule.capturePostProcessingDelegate = nil
-                capturePostProcessingDelegateAdapter.set(target: nil)
-            }
+            capturePostProcessingDelegateAdapter.set(target: capturePostProcessingDelegate, oldTarget: oldValue)
             capturePostProcessingDelegateSubject.send(capturePostProcessingDelegate)
         }
     }
@@ -147,15 +147,7 @@
     /// - Note: If you need to observe the buffer for individual tracks, use ``RemoteAudioTrack/add(audioRenderer:)`` instead
     public var renderPreProcessingDelegate: AudioCustomProcessingDelegate? {
         didSet {
-            if let renderPreProcessingDelegate {
-                // Clear WebRTC delegate first - this triggers release() on the old target
-                RTC.audioProcessingModule.renderPreProcessingDelegate = nil
-                renderPreProcessingDelegateAdapter.set(target: renderPreProcessingDelegate)
-                RTC.audioProcessingModule.renderPreProcessingDelegate = renderPreProcessingDelegateAdapter
-            } else {
-                RTC.audioProcessingModule.renderPreProcessingDelegate = nil
-                renderPreProcessingDelegateAdapter.set(target: nil)
-            }
+            renderPreProcessingDelegateAdapter.set(target: renderPreProcessingDelegate, oldTarget: oldValue)
         }
     }
 

Sources/LiveKit/Protocols/AudioCustomProcessingDelegate.swift

@@ -57,16 +57,53 @@ class AudioCustomProcessingDelegateAdapter: MulticastDelegate<AudioRenderer>, @u
 
     private var _state = StateSync(State())
 
-    func set(target: AudioCustomProcessingDelegate?) {
+    private let rtcDelegateGetter: () -> LKRTCAudioCustomProcessingDelegate?
+    private let rtcDelegateSetter: (LKRTCAudioCustomProcessingDelegate?) -> Void
+
+    func set(target: AudioCustomProcessingDelegate?, oldTarget: AudioCustomProcessingDelegate? = nil) {
+        // Clear WebRTC delegate first if there's an old target - this triggers audioProcessingRelease() on it
+        if oldTarget != nil {
+            rtcDelegateSetter(nil)
+        }
         _state.mutate { $0.target = target }
+        updateRTCConnection()
     }
 
-    init(label: String) {
+    init(label: String,
+         rtcDelegateGetter: @escaping () -> LKRTCAudioCustomProcessingDelegate?,
+         rtcDelegateSetter: @escaping (LKRTCAudioCustomProcessingDelegate?) -> Void)
+    {
         self.label = label
+        self.rtcDelegateGetter = rtcDelegateGetter
+        self.rtcDelegateSetter = rtcDelegateSetter
         super.init(label: "AudioCustomProcessingDelegateAdapter.\(label)")
         log("label: \(label)")
     }
 
+    // Override add/remove to manage RTC connection
+    override func add(delegate: AudioRenderer) {
+        super.add(delegate: delegate)
+        updateRTCConnection()
+    }
+
+    override func remove(delegate: AudioRenderer) {
+        super.remove(delegate: delegate)
+        updateRTCConnection()
+    }
+
+    private func updateRTCConnection() {
+        let shouldBeConnected = target != nil || isDelegatesNotEmpty
+        let isConnected = rtcDelegateGetter() === self
+
+        if shouldBeConnected, !isConnected {
+            // Connect
+            rtcDelegateSetter(self)
+        } else if !shouldBeConnected, isConnected {
+            // Disconnect
+            rtcDelegateSetter(nil)
+        }
+    }
+
     // MARK: - AudioCustomProcessingDelegate
 
     func audioProcessingInitialize(sampleRate sampleRateHz: Int, channels: Int) {

Tests/LiveKitAudioTests/AudioProcessingLifecycle.swift

@@ -66,11 +66,7 @@ class AudioProcessingLifecycle: LKTestCase {
             let room1 = rooms[0]
             // Publish mic
             try await room1.localParticipant.setMicrophone(enabled: true)
-            do {
-                // 1 secs...
-                let ns = UInt64(1 * 1_000_000_000)
-                try await Task.sleep(nanoseconds: ns)
-            }
+            await self.sleep(forSeconds: 1)
 
             // Verify processorA was initialized and received audio
             let stateA = processorA._state.copy()
@@ -79,11 +75,7 @@ class AudioProcessingLifecycle: LKTestCase {
 
             // Switch to processorB
             AudioManager.shared.capturePostProcessingDelegate = processorB
-            do {
-                // 1 secs...
-                let ns = UInt64(1 * 1_000_000_000)
-                try await Task.sleep(nanoseconds: ns)
-            }
+            await self.sleep(forSeconds: 1)
 
             // Verify processorA was released
             let stateA2 = processorA._state.copy()
@@ -102,4 +94,53 @@ class AudioProcessingLifecycle: LKTestCase {
         let stateB2 = processorB._state.copy()
         XCTAssertTrue(stateB2.entries.contains(.release), "Processor B should have been released")
     }
+
+    func testLocalAudioTrackRendererAPI() async throws {
+        try await withRooms([RoomTestingOptions(canPublish: true)]) { rooms in
+            let room1 = rooms[0]
+
+            // Create a test renderer
+            let renderer = TestAudioRenderer()
+
+            // Publish microphone
+            try await room1.localParticipant.setMicrophone(enabled: true)
+
+            // Get the local audio track
+            guard let localAudioTrack = room1.localParticipant.audioTracks.first?.track as? LocalAudioTrack else {
+                XCTFail("No local audio track found")
+                return
+            }
+
+            // Add renderer via LocalAudioTrack extension method
+            localAudioTrack.add(audioRenderer: renderer)
+
+            // Wait for audio to flow
+            await self.sleep(forSeconds: 1)
+
+            // Verify renderer received audio
+            let count = renderer.renderCount.copy()
+            XCTAssertGreaterThan(count, 0, "Renderer should have received audio buffers via LocalAudioTrack.add()")
+
+            // Remove renderer
+            localAudioTrack.remove(audioRenderer: renderer)
+
+            // Reset count
+            renderer.renderCount.mutate { $0 = 0 }
+
+            // Wait a bit
+            await self.sleep(forSeconds: 1)
+
+            // Verify no more audio is received
+            let countAfterRemove = renderer.renderCount.copy()
+            XCTAssertEqual(countAfterRemove, 0, "Renderer should not receive audio after removal")
+        }
+    }
+}
+
+private class TestAudioRenderer: AudioRenderer, @unchecked Sendable {
+    let renderCount = StateSync<Int>(0)
+
+    func render(pcmBuffer _: AVAudioPCMBuffer) {
+        renderCount.mutate { $0 += 1 }
+    }
 }

Tests/LiveKitAudioTests/LocalAudioTrackRecorderTests.swift

@@ -165,26 +165,6 @@
         XCTAssertGreaterThan(dataCount2, 0, "Should have received audio data from recorder2")
     }
 
-    func testStartingTwice() async throws {
-        let localTrack = LocalAudioTrack.createTrack(options: .noProcessing)
-
-        let recorder = LocalAudioTrackRecorder(
-            track: localTrack,
-            format: .pcmFormatInt16,
-            sampleRate: 48000
-        )
-
-        for await _ in try await recorder.start().prefix(10) {
-            // swiftformat:disable hoistAwait
-            await XCTAssertThrowsErrorAsync(try await recorder.start())
-            recorder.stop()
-        }
-
-        _ = try await recorder.start()
-
-        recorder.stop()
-    }
-
     func testObjCCompatibility() async throws {
         let localTrack = LocalAudioTrack.createTrack(options: .noProcessing)
 
@@ -198,7 +178,7 @@
         let completionExpectation = expectation(description: "Completion called")
         dataExpectation.assertForOverFulfill = false
 
         recorder.start(onData: { _ in
             dataExpectation.fulfill()
         }, onCompletion: { _ in
             completionExpectation.fulfill()

Tests/LiveKitCoreTests/Token/TokenSourceTests.swift

@@ -15,7 +15,9 @@
  */
 
 @testable import LiveKit
+#if canImport(LiveKitTestSupport)
 import LiveKitTestSupport
+#endif
 
 class TokenSourceTests: LKTestCase {
     actor MockValidJWTSource: TokenSourceConfigurable {