test: add tests to cover timezone/locale emulation in workers (#39132)

Author: aslushnikov

tests/library/browsercontext-locale.spec.ts

@@ -165,16 +165,19 @@ it('should not change default locale in another context', async ({ browser }) =>
   }
 });
 
-it('should format number in workers', async ({ browser, browserName, server }) => {
+it('should propagate locale to workers', async ({ browser, browserName, server }) => {
   it.fail(browserName === 'firefox', 'https://github.com/microsoft/playwright/issues/38919');
   const context = await browser.newContext({ locale: 'ru-RU' });
   const page = await context.newPage();
   await page.goto(server.EMPTY_PAGE);
-  const [worker] = await Promise.all([
-    page.waitForEvent('worker'),
-    page.evaluate(() => new Worker(URL.createObjectURL(new Blob(['console.log(1)'], { type: 'application/javascript' })))),
+  const [msg] = await Promise.all([
+    page.waitForEvent('console'),
+    page.evaluate(() => new Worker(URL.createObjectURL(new Blob(['console.log(Intl.NumberFormat().resolvedOptions().locale)'], { type: 'application/javascript' })))),
   ]);
-  expect(await worker.evaluate(() => (10000.20).toLocaleString())).toBe('10\u00A0000,2');
+  if (browserName === 'webkit')
+    expect(msg.text()).toContain('ru'); // Webkit on Ubuntu is "ru-RU", and on other platforms is "ru"
+  else
+    expect(msg.text()).toBe('ru-RU');
   await context.close();
 });
 

tests/library/browsercontext-timezone-id.spec.ts

@@ -115,3 +115,16 @@ it('should affect Intl.DateTimeFormat().resolvedOptions().timeZone', async ({ br
   expect(await page.evaluate(() => (new Intl.DateTimeFormat()).resolvedOptions().timeZone)).toBe('America/Jamaica');
   await context.close();
 });
+
+it('should propagate timezone to workers', async ({ browser, browserName, server }) => {
+  it.fail(browserName === 'firefox', 'https://github.com/microsoft/playwright/issues/38919');
+  const context = await browser.newContext({ timezoneId: 'America/Jamaica' });
+  const page = await context.newPage();
+  await page.goto(server.EMPTY_PAGE);
+  const [msg] = await Promise.all([
+    page.waitForEvent('console'),
+    page.evaluate(() => new Worker(URL.createObjectURL(new Blob(['console.log(Intl.DateTimeFormat().resolvedOptions().timeZone)'], { type: 'application/javascript' })))),
+  ]);
+  expect(msg.text()).toBe('America/Jamaica');
+  await context.close();
+});