fix(setupWorker): handle in-flight requests regardless of fake timers

test/browser/third-party/fake-timers.mock.js

@@ -0,0 +1,10 @@
+import { http, HttpResponse } from 'msw'
+import { setupWorker } from 'msw/browser'
+
+const worker = setupWorker(
+  http.get('/resource', () => {
+    return HttpResponse.text('hello world')
+  }),
+)
+
+worker.start()

test/browser/third-party/fake-timers.test.ts

@@ -0,0 +1,17 @@
+import { test, expect } from '../playwright.extend'
+
+test('mocks responses when using fake timers in tests', async ({
+  loadExample,
+  page,
+  fetch,
+}) => {
+  await loadExample(new URL('./fake-timers.mock.js', import.meta.url))
+
+  await page.evaluate(() => {
+    Date.now = () => 0
+  })
+
+  const response = await fetch('/resource')
+
+  await expect(response.text()).resolves.toBe('hello world')
+})