chore: only do single threaded tests for win

tests/integration/utils/dev-server.ts

@@ -71,7 +71,10 @@ const startServer = async ({
   skipWaitPort = false,
   targetPort,
 }: DevServerOptions): Promise<DevServer | { timeout: boolean; output: string }> => {
-  const port = await getPort()
+  // Use worker-specific port ranges to avoid conflicts in parallel execution
+  const workerId = process.env.VITEST_WORKER_ID || '1'
+  const workerOffset = (parseInt(workerId) - 1) * 100
+  const port = await getPort({ port: getPort.makeRange(3000 + workerOffset, 3000 + workerOffset + 99) })
   const host = 'localhost'
   const url = `http://${host}:${port}`
 
@@ -89,7 +92,8 @@ const startServer = async ({
   if (targetPort) {
     baseArgs.push('--target-port', targetPort.toString())
   } else {
-    const staticPort = await getPort()
+    // Use same worker-specific range for static port
+    const staticPort = await getPort({ port: getPort.makeRange(4000 + workerOffset, 4000 + workerOffset + 99) })
     baseArgs.push('--staticServerPort', staticPort.toString())
   }
 
@@ -158,7 +162,18 @@ const startServer = async ({
             },
             close: async () => {
               selfKilled = true
-              await killProcess(ps)
+              // Enhanced cleanup for Windows to handle Next.js child processes
+              if (process.platform === 'win32' && ps.pid) {
+                try {
+                  // Kill process tree on Windows to ensure all child processes are terminated
+                  await execa('taskkill', ['/pid', ps.pid.toString(), '/T', '/F'])
+                } catch {
+                  // Fallback to standard kill if taskkill fails
+                  await killProcess(ps)
+                }
+              } else {
+                await killProcess(ps)
+              }
             },
             promptHistory,
           })

vitest.config.ts

@@ -18,13 +18,7 @@ export default defineConfig({
       escapeString: true,
     },
     // Pin to vitest@1 behavior: https://vitest.dev/guide/migration.html#default-pool-is-forks.
-    // TODO(serhalp) Remove this and fix hanging `next-app-without-config` fixture on Windows.
     pool: 'threads',
-    poolOptions: {
-      threads: {
-        singleThread: true,
-      },
-    },
     coverage: {
       provider: 'v8',
       reporter: ['text', 'lcov'],

vitest.e2e.config.ts

@@ -5,12 +5,6 @@ export default defineConfig({
     include: ['e2e/**/*.e2e.[jt]s'],
     testTimeout: 1200_000,
     // Pin to vitest@1 behavior: https://vitest.dev/guide/migration.html#default-pool-is-forks.
-    // TODO(serhalp) Remove this and fix flaky hanging e2e tests on Windows.
     pool: 'threads',
-    poolOptions: {
-      threads: {
-        singleThread: true,
-      },
-    },
   },
 })