fix: snapshot infrared fake calls

testing/fakes/src/main/kotlin/com/flagship/abox/manager/testing/fakes/FakeDeviceGateways.kt

@@ -12,8 +12,8 @@ import com.flagship.abox.manager.domain.SocketPowerState
 import com.flagship.abox.manager.domain.SocketStatus
 import com.flagship.abox.manager.domain.TemperatureHumidityGateway
 import com.flagship.abox.manager.domain.TemperatureHumidityReading
-import java.util.Collections
 import java.util.concurrent.ConcurrentHashMap
+import java.util.concurrent.CopyOnWriteArrayList
 
 class FakeSocketGateway : SocketGateway {
     private val states = ConcurrentHashMap<DeviceKey, SocketPowerState>()
@@ -78,10 +78,9 @@ class FakeTemperatureHumidityGateway : TemperatureHumidityGateway {
 }
 
 class FakeInfraredGateway : InfraredGateway {
-    val sentKeys: MutableList<InfraredCall> = Collections.synchronizedList(mutableListOf())
+    val sentKeys = CopyOnWriteArrayList<InfraredCall>()
-    val learnedKeys: MutableList<InfraredCall> = Collections.synchronizedList(mutableListOf())
+    val learnedKeys = CopyOnWriteArrayList<InfraredCall>()
-    val downloadCalls: MutableList<InfraredDownloadCall> =
+    val downloadCalls = CopyOnWriteArrayList<InfraredDownloadCall>()
-        Collections.synchronizedList(mutableListOf())
     private val sendResults = ConcurrentHashMap<InfraredOperationKey, DomainResult<Unit>>()
     private val learnResults = ConcurrentHashMap<InfraredOperationKey, DomainResult<Unit>>()
 
@@ -134,9 +133,12 @@ class FakeInfraredGateway : InfraredGateway {
         profileId: ProviderProfileId,
         codes: List<InfraredCode>,
     ): DomainResult<List<InfraredCodeDownloadResult>> {
+        val codesSnapshot = codes.toList()
         downloadError?.let { return DomainResult.Failure(it) }
-        downloadCalls += InfraredDownloadCall(profileId, codes)
+        downloadCalls += InfraredDownloadCall(profileId, codesSnapshot)
-        return DomainResult.Success(codes.map { InfraredCodeDownloadResult(it, successful = true) })
+        return DomainResult.Success(
+            codesSnapshot.map { InfraredCodeDownloadResult(it, successful = true) },
+        )
     }
 }
 

testing/fakes/src/test/kotlin/com/flagship/abox/manager/testing/fakes/FakeDeviceGatewaysTest.kt

@@ -4,8 +4,14 @@ import com.flagship.abox.manager.domain.DeviceName
 import com.flagship.abox.manager.domain.DomainError
 import com.flagship.abox.manager.domain.DomainResult
 import com.flagship.abox.manager.domain.InfraredCode
+import com.flagship.abox.manager.domain.InfraredCodeDownloadResult
 import com.flagship.abox.manager.domain.ProviderProfileId
 import com.flagship.abox.manager.domain.SocketPowerState
+import java.util.concurrent.ConcurrentLinkedQueue
+import java.util.concurrent.CountDownLatch
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.joinAll
+import kotlinx.coroutines.launch
 import kotlinx.coroutines.test.runTest
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertTrue
@@ -55,6 +61,69 @@ class FakeDeviceGatewaysTest {
         assertTrue(download is DomainResult.Success)
     }
 
+    @Test
+    fun infraredDownloadRecordsAndReturnsAnInputSnapshot() = runTest {
+        val gateway = FakeInfraredGateway()
+        val code = InfraredCode(DeviceName("ir-1"), "power", "code-value")
+        val mutableCodes = mutableListOf(code)
+
+        val result = gateway.downloadCodes(profileOne, mutableCodes)
+        mutableCodes.clear()
+
+        assertEquals(
+            InfraredDownloadCall(profileOne, listOf(code)),
+            gateway.downloadCalls.single(),
+        )
+        assertEquals(
+            DomainResult.Success(listOf(InfraredCodeDownloadResult(code, successful = true))),
+            result,
+        )
+    }
+
+    @Test
+    fun infraredCallLogCanBeIteratedSafelyAroundConcurrentWrites() = runTest {
+        val gateway = FakeInfraredGateway()
+        val deviceName = DeviceName("ir-1")
+        gateway.sendKey(profileOne, deviceName, "initial")
+        val staleIterators = List(10) { gateway.sentKeys.iterator() }
+        val start = CountDownLatch(1)
+        val failures = ConcurrentLinkedQueue<Throwable>()
+        val writerCount = 4
+        val callsPerWriter = 100
+
+        val writers = List(writerCount) { writerIndex ->
+            launch(Dispatchers.Default) {
+                start.await()
+                repeat(callsPerWriter) { callIndex ->
+                    gateway.sendKey(profileOne, deviceName, "$writerIndex-$callIndex")
+                }
+            }
+        }
+        val reader = launch(Dispatchers.Default) {
+            start.await()
+            repeat(100) {
+                try {
+                    gateway.sentKeys.forEach { call -> call.key.length }
+                } catch (failure: Throwable) {
+                    failures += failure
+                }
+            }
+        }
+
+        start.countDown()
+        (writers + reader).joinAll()
+        staleIterators.forEach { iterator ->
+            try {
+                iterator.forEachRemaining { call -> call.key.length }
+            } catch (failure: Throwable) {
+                failures += failure
+            }
+        }
+
+        assertTrue(failures.toList().joinToString(), failures.isEmpty())
+        assertEquals(1 + writerCount * callsPerWriter, gateway.sentKeys.size)
+    }
+
     @Test
     fun infraredLearnResultsCanDifferByProfileDeviceAndKey() = runTest {
         val gateway = FakeInfraredGateway()