test: add page.bringToFront test (#4778)

Test `page.bringToFront` in headful.

test/headful.spec.js

@@ -117,5 +117,25 @@ module.exports.addTests = function({testRunner, expect, puppeteer, defaultBrowse
       await browser.close();
     });
   });
+
+  describe('Page.bringToFront', function() {
+    it('should work', async() => {
+      const browser = await puppeteer.launch(headfulOptions);
+      const page1 = await browser.newPage();
+      const page2 = await browser.newPage();
+
+      await page1.bringToFront();
+      expect(await page1.evaluate(() => document.visibilityState)).toBe('visible');
+      expect(await page2.evaluate(() => document.visibilityState)).toBe('hidden');
+
+      await page2.bringToFront();
+      expect(await page1.evaluate(() => document.visibilityState)).toBe('hidden');
+      expect(await page2.evaluate(() => document.visibilityState)).toBe('visible');
+
+      await page1.close();
+      await page2.close();
+      await browser.close();
+    });
+  });
 };
 

test/test.js

@@ -73,7 +73,6 @@ beforeEach(async({server, httpsServer}) => {
 });
 
 const CHROMIUM_NO_COVERAGE = new Set([
-  'page.bringToFront',
 ]);
 
 if (process.env.BROWSER === 'firefox') {