Fix runtime review findings

src/MxGateway.Tests/Gateway/Workers/WorkerClientTests.cs

@@ -137,6 +137,36 @@ public sealed class WorkerClientTests
         Assert.Equal(WorkerClientState.Faulted, client.State);
     }
 
+    [Fact]
+    public async Task ReadLoop_WhenClientFaults_KillsOwnedWorkerProcess()
+    {
+        await using PipePair pipePair = await PipePair.CreateAsync();
+        FakeWorkerProcess process = new();
+        await using WorkerClient client = CreateClient(
+            pipePair,
+            new WorkerClientOptions
+            {
+                EventChannelCapacity = 1,
+                HeartbeatGrace = TimeSpan.FromSeconds(30),
+                HeartbeatCheckInterval = TimeSpan.FromSeconds(30),
+            },
+            processHandle: CreateProcessHandle(process));
+        await CompleteHandshakeAsync(client, pipePair);
+
+        await pipePair.WorkerWriter.WriteAsync(
+            CreateEventEnvelope(sequence: 11, MxEventFamily.OnDataChange));
+        await pipePair.WorkerWriter.WriteAsync(
+            CreateEventEnvelope(sequence: 12, MxEventFamily.OnDataChange));
+
+        await WaitUntilAsync(
+            () => client.State == WorkerClientState.Faulted,
+            TestTimeout);
+
+        Assert.Equal(1, process.KillCount);
+        Assert.True(process.KillEntireProcessTree);
+        Assert.True(process.HasExited);
+    }
+
     [Fact]
     public async Task ReadLoop_WhenPipeDisconnects_FaultsClient()
     {
@@ -191,6 +221,20 @@ public sealed class WorkerClientTests
             $"DisposeAsync took {elapsed.TotalMilliseconds:N0}ms.");
     }
 
+    [Fact]
+    public async Task DisposeAsync_WhenOwnedWorkerStillRuns_KillsProcessBeforeDisposing()
+    {
+        await using PipePair pipePair = await PipePair.CreateAsync();
+        FakeWorkerProcess process = new();
+        WorkerClient client = CreateClient(pipePair, processHandle: CreateProcessHandle(process));
+
+        await client.DisposeAsync().AsTask().WaitAsync(TestTimeout);
+
+        Assert.Equal(1, process.KillCount);
+        Assert.True(process.KillEntireProcessTree);
+        Assert.True(process.Disposed);
+    }
+
     [Fact]
     public async Task ReadLoop_WhenHeartbeatArrives_UpdatesLastHeartbeatAndWorkerProcess()
     {
@@ -233,18 +277,28 @@ public sealed class WorkerClientTests
     private static WorkerClient CreateClient(
         PipePair pipePair,
         WorkerClientOptions? options = null,
-        GatewayMetrics? metrics = null)
+        GatewayMetrics? metrics = null,
+        WorkerProcessHandle? processHandle = null)
     {
         WorkerFrameProtocolOptions frameOptions = new(SessionId);
         WorkerClientConnection connection = new(
             SessionId,
             Nonce,
             pipePair.GatewayStream,
-            frameOptions);
+            frameOptions,
+            processHandle);
 
         return new WorkerClient(connection, options, metrics);
     }
 
+    private static WorkerProcessHandle CreateProcessHandle(FakeWorkerProcess process)
+    {
+        return new WorkerProcessHandle(
+            process,
+            new WorkerProcessCommandLine("MxGateway.Worker.exe", []),
+            DateTimeOffset.UtcNow);
+    }
+
     private static async Task CompleteHandshakeAsync(
         WorkerClient client,
         PipePair pipePair)
@@ -438,4 +492,40 @@ public sealed class WorkerClientTests
             await GatewayStream.DisposeAsync();
         }
     }
+
+    private sealed class FakeWorkerProcess : IWorkerProcess
+    {
+        private readonly TaskCompletionSource _exited = new(TaskCreationOptions.RunContinuationsAsynchronously);
+
+        public int Id { get; } = WorkerProcessId;
+
+        public bool HasExited { get; private set; }
+
+        public int? ExitCode { get; private set; }
+
+        public int KillCount { get; private set; }
+
+        public bool KillEntireProcessTree { get; private set; }
+
+        public bool Disposed { get; private set; }
+
+        public ValueTask WaitForExitAsync(CancellationToken cancellationToken)
+        {
+            return new ValueTask(_exited.Task.WaitAsync(cancellationToken));
+        }
+
+        public void Kill(bool entireProcessTree)
+        {
+            KillCount++;
+            KillEntireProcessTree = entireProcessTree;
+            HasExited = true;
+            ExitCode = -1;
+            _exited.TrySetResult();
+        }
+
+        public void Dispose()
+        {
+            Disposed = true;
+        }
+    }
 }