test: add Windows test for proxyVarSubDir

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: zkochan

os/env/path-extender-windows/path-extender-windows.spec.ts

@@ -148,6 +148,56 @@ HKEY_CURRENT_USER\\Environment
   expect(execa).toHaveBeenNthCalledWith(7, 'reg', ['delete' ,regKey, '/v', 'REFRESH_ENV_VARS', '/f'], { windowsHide: false })
 })
 
+test('successful first time installation with proxyVarSubDir', async () => {
+  const currentPathInRegistry = '%USERPROFILE%\\AppData\\Local\\Microsoft\\WindowsApps;%USERPROFILE%\\.config\\etc;'
+
+  execa['mockResolvedValueOnce']({
+    failed: false,
+    stdout: '活动代码页: 936',
+  }).mockResolvedValueOnce({
+    failed: false,
+    stdout: '',
+  }).mockResolvedValueOnce({
+    failed: false,
+    stdout: `
+HKEY_CURRENT_USER\\Environment
+    Path    REG_EXPAND_SZ    ${currentPathInRegistry}
+`,
+  }).mockResolvedValueOnce({
+    failed: false,
+    stdout: 'PNPM_HOME ENV VAR SET',
+  }).mockResolvedValueOnce({
+    failed: false,
+    stdout: 'setx PNPM_HOME',
+  }).mockResolvedValueOnce({
+    failed: false,
+    stdout: 'setx PNPM_HOME',
+  }).mockResolvedValue({
+    failed: true,
+    stderr: 'UNEXPECTED',
+  })
+
+  const pnpmHomeDir = tempDir(false)
+  const pnpmHomeDirNormalized = path.normalize(pnpmHomeDir)
+  const report = await addDirToWindowsEnvPath(pnpmHomeDir, { proxyVarName: 'PNPM_HOME', proxyVarSubDir: 'bin' })
+
+  expect(report).toStrictEqual([
+    {
+      action: 'updated',
+      variable: 'PNPM_HOME',
+      oldValue: undefined,
+      newValue: pnpmHomeDirNormalized,
+    },
+    {
+      action: 'updated',
+      variable: 'Path',
+      oldValue: currentPathInRegistry,
+      newValue: `%PNPM_HOME%\\bin;${currentPathInRegistry}`,
+    },
+  ])
+  expect(execa).toHaveBeenNthCalledWith(5, 'reg', ['add', regKey, '/v', 'Path', '/t', 'REG_EXPAND_SZ', '/d', `%PNPM_HOME%\\bin;${currentPathInRegistry}`, '/f'], { windowsHide: false })
+})
+
 test('successful first time installation when no additional env variable is used', async () => {
   const currentPathInRegistry = '%USERPROFILE%\\AppData\\Local\\Microsoft\\WindowsApps;%USERPROFILE%\\.config\\etc;'