Blind-Striker · Oct 16, 2026 · Oct 16, 2026 · Oct 16, 2026
@@ -953,7 +953,7 @@ dotnet_diagnostic.VSTHRD003.severity = none
 [tests/OpenCode.Sdk.Tests/Harness/Ownership/OwnedOperationDeadlineTests.cs]
 dotnet_diagnostic.VSTHRD003.severity = none
 
-[tests/OpenCode.Sdk.Tests/Support/SessionLogTranscriptTests.cs]
+[tests/OpenCode.Sdk.Tests/Sessions/Support/SessionLogTranscriptTests.cs]
 dotnet_diagnostic.VSTHRD003.severity = none
 
 # The session-removal fault proof controls interrupt entry and expiry, then drains cancellation
@@ -970,7 +970,7 @@ dotnet_diagnostic.VSTHRD003.severity = none
 # These diagnostic proofs control their own operation deadlines and retain supplied disposal
 # tasks until finally releases and drains them. Winner: causal fixture/status ownership proofs;
 # the rule remains enabled outside these exact files.
-[tests/OpenCode.Sdk.Tests/Support/PtyFailureDiagnosticsTests.cs]
+[tests/OpenCode.Sdk.Tests/Ptys/Support/PtyFailureDiagnosticsTests.cs]
 dotnet_diagnostic.VSTHRD003.severity = none
 
 [tests/OpenCode.Sdk.Tests/Support/ServerDiagnosticScenario.cs]
@@ -1155,7 +1155,7 @@ dotnet_diagnostic.MA0045.severity = none
 # DriveManifestTests.cs documents above - and an async factory would make the arrangement
 # awaitable without making it asynchronous. Winner: the cross-TFM arrangement shape; MA0045
 # remains enabled for every other file.
-[tests/OpenCode.Sdk.Tests/Support/PathCommandShim.cs]
+[tests/OpenCode.Sdk.Tests/Hosting/Launcher/Support/PathCommandShim.cs]
 dotnet_diagnostic.MA0045.severity = none
 
 # Optional<T> is the tri-state carrier for a request property the document declares both optional

@@ -1,6 +1,6 @@
 # Testing Style — authoring tests
 
-Date: 2026-10-16
+Date: 2026-10-17
 
 Binding authorship style for every test in this repository. `quality-gates.md` owns the
 current assurance posture and completion gates; operational build-out state belongs in
@@ -64,9 +64,11 @@ sized to need:
   like a BCL type shadows it there: tests under `Debug/` declare `OpenCode.Sdk.Tests.Debug` and
   qualify `System.Diagnostics.Debug`. A guard test refuses two source types that project onto
   one test path.
-- A helper or fixture one slice uses lives in that test slice's `Support/` or `Fixtures/`;
-  helpers several slices share stay in the test project's root `Support/`. Live-server harness
-  code lives in `tests/OpenCode.Sdk.Tests/Harness/`. Files another test project links, and the
+- In SDK.Tests, a helper or fixture used by one slice lives in that slice's `Support/` or
+  `Fixtures/`. Helpers and fixtures used by several slices stay in the test project's root
+  `Support/` and `Fixtures/`. Embedded fixtures retain their `Fixtures.` resource-name prefix
+  through explicit `LogicalName` metadata. Live-server harness code lives in
+  `tests/OpenCode.Sdk.Tests/Harness/`. Files another test project links, and the
   embedded-fixture loader, stay in `tests/Shared/`, compiled through explicit links. There is no
   separate test-support project.
 - The mirror rule also applies to test infrastructure: `Harness/X.cs` is tested in
@@ -99,8 +101,9 @@ analyzer enforces it wherever an abstractions assembly is referenced — even te
 **Raw JSON/XML/string-literal dumps pasted inline in test methods are forbidden.** A
 test body states *intent*; the data it runs on lives in one of three sanctioned homes:
 
-1. **Embedded fixture files** — under the owning test project's `Fixtures/` folder,
-   loaded through a resource-loader helper by name. The default for wire-shaped data:
+1. **Embedded fixture files** — in the `Fixtures/` folder of the slice that uses them, or the test
+   project's root `Fixtures/` when several slices share them, loaded through a resource-loader helper
+   by name. The default for wire-shaped data:
    one small file per quirk, named for the construct it isolates, reviewable on its own.
 2. **Typed builders** — for variation families where files would multiply: red tests
    composing a valid base plus exactly one offending construct through the builder. The

@@ -1,6 +1,7 @@
 using System.Net;
 using System.Net.Sockets;
 using OpenCode.Sdk.Internal;
+using OpenCode.Sdk.Tests.Hosting.BackgroundService.Support;
 using OpenCode.Sdk.Tests.Support;
 
 namespace OpenCode.Sdk.Tests.Hosting.BackgroundService.Discovery;

@@ -1,6 +1,7 @@
 using System.Globalization;
 using System.Net;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Hosting.BackgroundService.Support;
 using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions;
 

@@ -1,5 +1,6 @@
 using OpenCode.Sdk.Internal;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Hosting.BackgroundService.Support;
 using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions;
 

@@ -4,6 +4,7 @@
 using System.Text;
 using OpenCode.Sdk.Internal;
 using OpenCode.Sdk.Tests.Hosting.BackgroundService.Registration;
+using OpenCode.Sdk.Tests.Hosting.BackgroundService.Support;
 using OpenCode.Sdk.Tests.Support;
 
 namespace OpenCode.Sdk.Tests.Hosting.BackgroundService.Discovery;

@@ -1,6 +1,7 @@
 using System.Text;
 using OpenCode.Sdk.Internal;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Hosting.BackgroundService.Support;
 using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions;
 

@@ -1,6 +1,7 @@
 using System.Net;
 using NSubstitute;
 using OpenCode.Sdk.Internal;
+using OpenCode.Sdk.Tests.Hosting.BackgroundService.Support;
 using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions.Testing;
 

@@ -1,6 +1,6 @@
 using System.Net.Sockets;
 
-namespace OpenCode.Sdk.Tests.Support;
+namespace OpenCode.Sdk.Tests.Hosting.BackgroundService.Support;
 
 /// <summary>One connect the probe's loopback transport made itself, as <see cref="RecordingLoopbackConnector"/> saw it.</summary>
 /// <param name="SynRetransmissionDisabled">Whether the loopback option took on the socket it connected.</param>

@@ -2,7 +2,7 @@
 using System.Net.Sockets;
 using OpenCode.Sdk.Internal;
 
-namespace OpenCode.Sdk.Tests.Support;
+namespace OpenCode.Sdk.Tests.Hosting.BackgroundService.Support;
 
 /// <summary>
 /// The platform connect under the probe's loopback transport, recording each connect the transport

@@ -1,7 +1,7 @@
 #if !NET
 using OpenCode.Sdk.Internal;
 
-namespace OpenCode.Sdk.Tests.Support;
+namespace OpenCode.Sdk.Tests.Hosting.BackgroundService.Support;
 
 /// <summary>
 /// A loopback connect that completes in a chosen order, with no socket traffic: it cancels the

@@ -1,6 +1,6 @@
 using System.Globalization;
 
-namespace OpenCode.Sdk.Tests.Support;
+namespace OpenCode.Sdk.Tests.Hosting.BackgroundService.Support;
 
 /// <summary>
 /// The isolated discovery executable's output as a test reads it: the one stdout line for a found

@@ -1,7 +1,7 @@
 using System.Globalization;
 using OpenCode.Sdk.Internal;
 
-namespace OpenCode.Sdk.Tests.Support;
+namespace OpenCode.Sdk.Tests.Hosting.BackgroundService.Support;
 
 /// <summary>
 /// The probe bound of every background-service test about the probe's answer rather than its

@@ -1,7 +1,7 @@
 #if NET
 using System.Diagnostics.Tracing;
 
-namespace OpenCode.Sdk.Tests.Support;
+namespace OpenCode.Sdk.Tests.Hosting.BackgroundService.Support;
 
 /// <summary>
 /// Records this process's socket connect events while it lives, so a test can read that its own

@@ -1,5 +1,6 @@
 using OpenCode.Sdk.Internal;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions;
 

@@ -2,6 +2,7 @@
 using System.Globalization;
 using OpenCode.Sdk.Internal;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions;
 using TUnit.Assertions.Enums;

@@ -1,5 +1,6 @@
 using OpenCode.Sdk.Internal;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions;
 

@@ -5,6 +5,7 @@
 using Microsoft.Win32.SafeHandles;
 using OpenCode.Sdk.Internal;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions;
 

@@ -3,6 +3,7 @@
 using NSubstitute;
 using OpenCode.Sdk.Internal;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions;
 using TUnit.Assertions.Enums;

@@ -1,6 +1,7 @@
 using System.Diagnostics;
 using System.Globalization;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions;
 

@@ -3,6 +3,7 @@
 using NSubstitute;
 using OpenCode.Sdk.Internal;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions;
 

@@ -1,6 +1,8 @@
 using NSubstitute;
 using OpenCode.Sdk.Internal;
+using OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 using OpenCode.Sdk.Tests.Support;
+using SdkTestSupport = OpenCode.Sdk.Tests.Support;
 
 namespace OpenCode.Sdk.Tests.Hosting.Launcher;
 
@@ -149,7 +151,7 @@ public Task StartAsync_Should_Keep_A_Recorded_Exit_When_The_Caller_Cancels_Durin
         AssertRecordedAtTimeoutAsync(ExitCommand, EarlyExitDiagnostic, cancellationToken, static async (time, arbitrate, caller) =>
         {
             _ = arbitrate.TrySetResult();
-            await time.WaitForArmedAsync(OwnedServerChild.EarlyEndBound, Support.HangGuard.Bound, count: 2);
+            await time.WaitForArmedAsync(OwnedServerChild.EarlyEndBound, SdkTestSupport.HangGuard.Bound, count: 2);
             await caller.CancelOnWorkerAsync();
         });
 
@@ -180,10 +182,10 @@ private static async Task AssertRecordedAtTimeoutAsync(
         var starting = OpenCodeServer.StartWithSeamsAsync(RecordedOptions(publish), seams, caller.Token);
         try
         {
-            var recorded = await entered.Task.WaitAsync(Support.HangGuard.Bound, cancellationToken);
-            await time.WaitForArmedAsync(ReadinessBound, Support.HangGuard.Bound);
+            var recorded = await entered.Task.WaitAsync(SdkTestSupport.HangGuard.Bound, cancellationToken);
+            await time.WaitForArmedAsync(ReadinessBound, SdkTestSupport.HangGuard.Bound);
             time.Advance(ReadinessBound);
-            await canceled.Task.WaitAsync(Support.HangGuard.Bound, cancellationToken);
+            await canceled.Task.WaitAsync(SdkTestSupport.HangGuard.Bound, cancellationToken);
             // The spawn supplied stdin before the owner entered its wait.
             await PublishRecordedOutcomeAsync(recorded, input!, closingOutput, cancellationToken);
             if (closingOutput is not null)
@@ -263,11 +265,11 @@ private static async Task AssertRecordedAtTimeoutAsync(
     private static async Task PublishRecordedOutcomeAsync(
         Task recorded, Stream input, GatedStream? closingOutput, CancellationToken cancellationToken)
     {
-        await input.WriteAsync(new byte[] { 1 }, cancellationToken).AsTask().WaitAsync(Support.HangGuard.Bound, cancellationToken);
-        await input.FlushAsync(cancellationToken).WaitAsync(Support.HangGuard.Bound, cancellationToken);
+        await input.WriteAsync(new byte[] { 1 }, cancellationToken).AsTask().WaitAsync(SdkTestSupport.HangGuard.Bound, cancellationToken);
+        await input.FlushAsync(cancellationToken).WaitAsync(SdkTestSupport.HangGuard.Bound, cancellationToken);
         closingOutput?.Release();
         Task[] recordedTasks = [recorded];
-        await Task.WhenAll(recordedTasks).WaitAsync(Support.HangGuard.Bound, cancellationToken);
+        await Task.WhenAll(recordedTasks).WaitAsync(SdkTestSupport.HangGuard.Bound, cancellationToken);
     }
 
     private static async Task AssertCallerCancellationAsync(
@@ -289,11 +291,11 @@ private static async Task AdvanceEarlyEndAsync(
         ManualTimeProvider time, Task starting, int count, CancellationToken cancellationToken)
     {
         // A timeout can finish cleanup without a drain; a recorded early end drains first.
-        var draining = time.WaitForArmedAsync(OwnedServerChild.EarlyEndBound, Support.HangGuard.Bound, count);
+        var draining = time.WaitForArmedAsync(OwnedServerChild.EarlyEndBound, SdkTestSupport.HangGuard.Bound, count);
         Task[] startingTasks = [starting];
-        if (await Task.WhenAny(Task.WhenAll(startingTasks), draining).WaitAsync(Support.HangGuard.Bound, cancellationToken) == draining)
+        if (await Task.WhenAny(Task.WhenAll(startingTasks), draining).WaitAsync(SdkTestSupport.HangGuard.Bound, cancellationToken) == draining)
         {
-            await draining.WaitAsync(Support.HangGuard.Bound, cancellationToken);
+            await draining.WaitAsync(SdkTestSupport.HangGuard.Bound, cancellationToken);
             time.Advance(OwnedServerChild.EarlyEndBound);
         }
     }
@@ -340,13 +342,13 @@ private static Func<Task, CancellationToken, Task> HoldCanceledWait(
         try
         {
             Task[] pendingTasks = [pending];
-            await Task.WhenAll(pendingTasks).WaitAsync(token).WaitAsync(Support.HangGuard.Bound, cancellationToken);
+            await Task.WhenAll(pendingTasks).WaitAsync(token).WaitAsync(SdkTestSupport.HangGuard.Bound, cancellationToken);
         }
         catch (OperationCanceledException) when (token.IsCancellationRequested)
         {
             _ = canceled.TrySetResult();
             Task[] arbitrationTasks = [arbitrate.Task];
-            await Task.WhenAll(arbitrationTasks).WaitAsync(Support.HangGuard.Bound, cancellationToken);
+            await Task.WhenAll(arbitrationTasks).WaitAsync(SdkTestSupport.HangGuard.Bound, cancellationToken);
             throw;
         }
     };
@@ -364,7 +366,7 @@ private static async Task AssertStartOutcomeAsync(
         }
         else
         {
-            await Assert.That(async () => await Task.WhenAll(startingTasks).WaitAsync(Support.HangGuard.Bound, cancellationToken)).ThrowsNothing();
+            await Assert.That(async () => await Task.WhenAll(startingTasks).WaitAsync(SdkTestSupport.HangGuard.Bound, cancellationToken)).ThrowsNothing();
             var server = await startingTasks[0];
             await Assert.That(server.Endpoint).IsEqualTo(new Uri(ReadyEndpoint));
             await Assert.That(server.ChildExited.IsCompleted).IsFalse();
@@ -397,7 +399,7 @@ await starting.ContinueWith(static completed => _ = completed.Exception, Cancell
                 {
                     if (originalOutput is not null)
                     {
-                        await originalOutput.DisposeAsync().AsTask().WaitAsync(Support.HangGuard.Bound);
+                        await originalOutput.DisposeAsync().AsTask().WaitAsync(SdkTestSupport.HangGuard.Bound);
                     }
                 }
                 finally

@@ -1,6 +1,7 @@
 using System.Globalization;
 using OpenCode.Sdk.Internal;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions;
 

@@ -1,6 +1,7 @@
 using System.Globalization;
 using OpenCode.Sdk.Internal;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions;
 

@@ -2,6 +2,7 @@
 using System.Text;
 using NSubstitute;
 using OpenCode.Sdk.Internal;
+using OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 using OpenCode.Sdk.Tests.Support;
 using TUnit.Assertions.Enums;
 

@@ -1,8 +1,9 @@
 using System.Globalization;
 using OpenCode.Sdk.Internal;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Support;
 
-namespace OpenCode.Sdk.Tests.Support;
+namespace OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 
 /// <summary>
 /// The <c>ladder-tree.js</c> server stand-in: a root with the children a flag list asks for, each

@@ -6,9 +6,10 @@
 using Microsoft.Win32.SafeHandles;
 using OpenCode.Sdk.Internal;
 using OpenCode.Sdk.Tests.Harness;
+using OpenCode.Sdk.Tests.Support;
 using Testably.Abstractions;
 
-namespace OpenCode.Sdk.Tests.Support;
+namespace OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 
 /// <summary>
 /// The service fixture's <c>launcher-host</c> mode: a separate .NET process that owns one

@@ -1,4 +1,4 @@
-namespace OpenCode.Sdk.Tests.Support;
+namespace OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 
 /// <summary>The signal a <see cref="LauncherHost"/> starts with ignored, inherited the way a real host inherits it.</summary>
 internal enum LauncherHostIgnores

@@ -1,6 +1,6 @@
 using OpenCode.Sdk.Internal;
 
-namespace OpenCode.Sdk.Tests.Support;
+namespace OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 
 /// <summary>
 /// A C library without <c>posix_spawn_file_actions_addchdir_np</c>, as glibc before 2.29 is: the

@@ -2,7 +2,7 @@
 using System.Text;
 using OpenCode.Sdk.Tests.Harness;
 
-namespace OpenCode.Sdk.Tests.Support;
+namespace OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 
 /// <summary>
 /// An npm-shaped command shim on the process PATH: a temporary directory holding one Windows

@@ -1,6 +1,6 @@
 using OpenCode.Sdk.Internal;
 
-namespace OpenCode.Sdk.Tests.Support;
+namespace OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 
 /// <summary>
 /// The real exit-status seam, reporting that the kernel reaps this process's children itself, as

@@ -2,7 +2,7 @@
 using System.Diagnostics;
 using OpenCode.Sdk.Internal;
 
-namespace OpenCode.Sdk.Tests.Support;
+namespace OpenCode.Sdk.Tests.Hosting.Launcher.Support;
 
 /// <summary>
 /// The shipped Windows tree kill behind a recorder: every run is recorded with the time since the