Strengthen SaidIt service tests with Robolectric coverage

SaidIt/src/main/java/eu/mrogalski/saidit/AudioMemory.kt

@@ -8,7 +8,7 @@ import java.nio.ByteBuffer
  * Modern Kotlin implementation of AudioMemory with Result<T> error handling.
  * Manages a ring buffer for audio data with improved error handling and thread safety.
  */
-class AudioMemory(private val clock: Clock) {
+open class AudioMemory(private val clock: Clock) {
 
     companion object {
         // Keep chunk size as allocation granularity (20s @ 48kHz mono 16-bit)
@@ -54,7 +54,7 @@ class AudioMemory(private val clock: Clock) {
      * @return Result<Unit> indicating success or failure
      */
     @Synchronized
-    fun allocate(sizeToEnsure: Long): Result<Unit> {
+    open fun allocate(sizeToEnsure: Long): Result<Unit> {
         return try {
             var required = 0
             while (required < sizeToEnsure) required += CHUNK_SIZE
@@ -215,7 +215,7 @@ class AudioMemory(private val clock: Clock) {
      * @return Result<Unit> indicating success or failure
      */
     @Synchronized
-    fun dump(consumer: Consumer, bytesToDump: Int): Result<Unit> {
+    open fun dump(consumer: Consumer, bytesToDump: Int): Result<Unit> {
         if (capacity == 0 || ring == null || size == 0 || bytesToDump <= 0) {
             return Result.success(Unit)
         }

SaidIt/src/main/java/eu/mrogalski/saidit/SaidItService.kt

@@ -64,11 +64,36 @@ class SaidItService : Service() {
 
     private var mediaFile: File? = null
     private var audioRecord: AudioRecord? = null
-    private var aacWriter: AacMp4Writer? = null
-    private val audioMemory = AudioMemory(SystemClockWrapper())
+    private var audioWriter: AudioSampleWriter? = null
+    private var audioMemory: AudioMemory = AudioMemory(SystemClockWrapper())
 
     // Coroutine scope for audio operations
-    private val audioScope = CoroutineScope(Dispatchers.Default + SupervisorJob())
+    private var audioDispatcher: CoroutineDispatcher = Dispatchers.Default
+    private var audioScope = CoroutineScope(audioDispatcher + SupervisorJob())
+
+    @VisibleForTesting
+    internal var audioSampleWriterFactory: (Int, Int, Int, File) -> AudioSampleWriter =
+        { sampleRate, channels, bitRate, file ->
+            AacMp4Writer(sampleRate, channels, bitRate, file)
+        }
+
+    @VisibleForTesting
+    internal fun overrideAudioMemoryForTest(memory: AudioMemory) {
+        audioMemory = memory
+    }
+
+    @VisibleForTesting
+    internal fun audioMemoryForTest(): AudioMemory = audioMemory
+
+    @VisibleForTesting
+    internal fun overrideAudioDispatcherForTest(dispatcher: CoroutineDispatcher) {
+        audioScope.cancel()
+        audioDispatcher = dispatcher
+        audioScope = CoroutineScope(audioDispatcher + SupervisorJob())
+    }
+
+    @VisibleForTesting
+    internal fun stateForTest(): Int = state
     private var audioJob: Job? = null
 
     @Volatile
@@ -188,8 +213,8 @@ class SaidItService : Service() {
                     Log.e(TAG, "AUDIO RECORD ERROR: $read")
                     return@Consumer Result.success(0)
                 }
-                if (aacWriter != null && read > 0) {
-                    aacWriter?.write(array, offset, read)
+                if (audioWriter != null && read > 0) {
+                    audioWriter?.write(array, offset, read)
                 }
                 Result.success(read)
             } ?: Result.success(0)
@@ -263,19 +288,19 @@ class SaidItService : Service() {
             try {
                 if (isTestEnvironment) {
                     mediaFile = null
-                    aacWriter = null
+                    audioWriter = null
                     return@launch
                 }
-                
+
                 mediaFile = File.createTempFile("saidit", ".m4a", cacheDir)
-                aacWriter = AacMp4Writer(sampleRate, 1, 96_000, mediaFile!!)
+                audioWriter = audioSampleWriterFactory(sampleRate, 1, 96_000, mediaFile!!)
                 Log.d(TAG, "Recording to: ${mediaFile!!.absolutePath}")
 
                 if (prependedMemorySeconds > 0) {
                     val bytesPerSecond = (1f / getBytesToSeconds()).toInt()
                     val bytesToDump = (prependedMemorySeconds * bytesPerSecond).toInt()
                     audioMemory.dump(AudioMemory.LegacyConsumer { array, offset, count ->
-                        aacWriter?.write(array, offset, count)
+                        audioWriter?.write(array, offset, count)
                         count
                     }, bytesToDump)
                 }
@@ -295,18 +320,18 @@ class SaidItService : Service() {
 
         audioScope.launch {
             flushAudioRecord()
-            aacWriter?.let { writer ->
+            audioWriter?.let { writer ->
                 try {
                     writer.close()
                 } catch (e: IOException) {
                     Log.e(TAG, "CLOSING ERROR", e)
                 }
             }
-            
+
             if (wavFileReceiver != null && mediaFile != null) {
                 saveFileToMediaStore(mediaFile!!, mediaFile!!.name, wavFileReceiver)
             }
-            aacWriter = null
+            audioWriter = null
         }
     }
 
@@ -329,7 +354,7 @@ class SaidItService : Service() {
 
                 val fileName = newFileName?.replace("[^a-zA-Z0-9.-]".toRegex(), "_") ?: "SaidIt_dump"
                 dumpFile = File(cacheDir, "$fileName.m4a")
-                val dumper = AacMp4Writer(sampleRate, 1, 96_000, dumpFile)
+                val dumper = audioSampleWriterFactory(sampleRate, 1, 96_000, dumpFile)
                 Log.d(TAG, "Dumping to: ${dumpFile.absolutePath}")
 
                 val bytesPerSecond = (1f / getBytesToSeconds()).toInt()
@@ -461,7 +486,7 @@ class SaidItService : Service() {
             val stats = audioMemory.getStats(fillRate)
 
             var recorded = 0
-            aacWriter?.let { writer ->
+            audioWriter?.let { writer ->
                 recorded += writer.getTotalSampleBytesWritten()
                 recorded += stats.estimation
             }

SaidIt/src/main/kotlin/eu/mrogalski/saidit/AacMp4Writer.kt

@@ -5,7 +5,6 @@ import android.media.MediaCodecInfo
 import android.media.MediaFormat
 import android.media.MediaMuxer
 import android.util.Log
-import java.io.Closeable
 import java.io.File
 import java.io.IOException
 import java.nio.ByteBuffer
@@ -67,7 +66,7 @@ class AacMp4Writer(
     outFile: File,
     private val codecFactory: MediaCodecFactory = DefaultMediaCodecFactory(),
     private val muxerFactory: MediaMuxerFactory = DefaultMediaMuxerFactory()
-) : Closeable {
+) : AudioSampleWriter {
 
     companion object {
         private const val TAG = "AacMp4Writer"
@@ -116,7 +115,7 @@ class AacMp4Writer(
      * @throws IOException if encoding or muxing fails
      */
     @Throws(IOException::class)
-    fun write(data: ByteArray, offset: Int, length: Int) {
+    override fun write(data: ByteArray, offset: Int, length: Int) {
         var remaining = length
         var off = offset
 
@@ -232,7 +231,7 @@ class AacMp4Writer(
      * Returns the total number of PCM sample bytes written.
      * Safe cast for typical audio file sizes.
      */
-    fun getTotalSampleBytesWritten(): Int {
+    override fun getTotalSampleBytesWritten(): Int {
         return minOf(Int.MAX_VALUE.toLong(), totalPcmBytesWritten).toInt()
     }
 }

SaidIt/src/main/kotlin/eu/mrogalski/saidit/AudioSampleWriter.kt

@@ -0,0 +1,15 @@
+package eu.mrogalski.saidit
+
+import java.io.Closeable
+import java.io.IOException
+
+/**
+ * Abstraction for classes that persist PCM audio samples.
+ * Allows SaidItService to swap implementations during tests.
+ */
+interface AudioSampleWriter : Closeable {
+    @Throws(IOException::class)
+    fun write(data: ByteArray, offset: Int, length: Int)
+
+    fun getTotalSampleBytesWritten(): Int
+}

SaidIt/src/test/kotlin/eu/mrogalski/saidit/MainDispatcherRule.kt

@@ -0,0 +1,24 @@
+package eu.mrogalski.saidit
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.StandardTestDispatcher
+import kotlinx.coroutines.test.TestDispatcher
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.setMain
+import org.junit.rules.TestWatcher
+import org.junit.runner.Description
+
+@OptIn(ExperimentalCoroutinesApi::class)
+class MainDispatcherRule(
+    val testDispatcher: TestDispatcher = StandardTestDispatcher()
+) : TestWatcher() {
+
+    override fun starting(description: Description?) {
+        Dispatchers.setMain(testDispatcher)
+    }
+
+    override fun finished(description: Description?) {
+        Dispatchers.resetMain()
+    }
+}