From 8fa531fefe58472c0df969158b5e3b0079938a9c Mon Sep 17 00:00:00 2001
From: ScriptedAlchemy <zackary.l.jackson@gmail.com>
Date: Fri, 25 Sep 2026 20:44:44 +0000
Subject: [PATCH] test(rstest): run the win32 rename mock test in an isolated
 pool

---
 docs/local-ci.md                 |  2 ++
 rstest.host-filesystem.config.ts |  3 ++-
 rstest.integration-tests.ts      | 10 ++++++++++
 rstest.unit.config.ts            |  2 ++
 4 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/docs/local-ci.md b/docs/local-ci.md
index 190aa2724..e1b6a268e 100644
--- a/docs/local-ci.md
+++ b/docs/local-ci.md
@@ -174,6 +174,8 @@ not build the Workbench e2e example payload):
 - `npm-cli-resolution.test.ts` (Windows official + Unix/nvm + PATH + split-prefix/pnpm `npm_execpath`)
 - `packed-install-bin.test.ts` (packaged installer bin from a consumer cwd)
 - `rstest-worker-isolation.test.ts` (canonical TMPDIR; macOS `/tmp` → `/private/tmp`)
+- `rstest-generated-module-win32-rename.test.ts` (transient Windows rename retry;
+  mocks `node:fs/promises`, so it needs this pool's per-file module isolation)
 
 That is the slice that can actually diverge by OS. macOS matters because
 Claude, Codex, and Cursor authors commonly develop there; Windows is in the
diff --git a/rstest.host-filesystem.config.ts b/rstest.host-filesystem.config.ts
index d0854955a..a7331cc4e 100644
--- a/rstest.host-filesystem.config.ts
+++ b/rstest.host-filesystem.config.ts
@@ -1,5 +1,6 @@
 import { defineConfig } from '@rstest/core';
 
+import { moduleMockTestFiles } from './rstest.integration-tests.ts';
 import {
   poolTimeouts,
   processPoolMaxWorkers,
@@ -33,7 +34,7 @@ export const hostFilesystemTestFiles = [
 
 export default defineConfig({
   extends: withAgentBundleRslibConfig(),
-  include: [...hostFilesystemTestFiles],
+  include: [...hostFilesystemTestFiles, ...moduleMockTestFiles],
   globalSetup: [...workspaceGlobalSetup],
   pool: { maxWorkers },
   setupFiles: [...workspaceSetupFiles],
diff --git a/rstest.integration-tests.ts b/rstest.integration-tests.ts
index b963a2daf..3eb43e529 100644
--- a/rstest.integration-tests.ts
+++ b/rstest.integration-tests.ts
@@ -234,3 +234,13 @@ export const templateTestFiles: readonly string[] = [
 export const fixtureProjectTestFiles: readonly string[] = [
   'packages/agent-bundle/fixtures/**/tests/**',
 ];
+
+/**
+ * Files that mock a module with `rs.mock`. The unit pool shares one module
+ * cache per worker (`isolate: false`), so the mock never reaches a module
+ * another file in that worker loaded first. They run in the per-file isolated
+ * `test:host-filesystem` pool instead.
+ */
+export const moduleMockTestFiles: readonly string[] = [
+  'packages/agent-bundle/tests/rstest-generated-module-win32-rename.test.ts',
+];
diff --git a/rstest.unit.config.ts b/rstest.unit.config.ts
index b3cbd3a6f..31ec4a51a 100644
--- a/rstest.unit.config.ts
+++ b/rstest.unit.config.ts
@@ -4,6 +4,7 @@ import {
   fixtureProjectTestFiles,
   integrationTestFiles,
   mcpConformanceTestFiles,
+  moduleMockTestFiles,
   nativeHostTestFiles,
   packedReleaseOnlyTestFiles,
   packedTestFiles,
@@ -30,6 +31,7 @@ export default defineConfig({
     ...fixtureProjectTestFiles,
     ...integrationTestFiles,
     ...mcpConformanceTestFiles,
+    ...moduleMockTestFiles,
     ...nativeHostTestFiles,
     // Packs and installs like packedTestFiles, and is release-boundary-only:
     // `test:packed:release` owns it, not the build-free per-PR pool.