Report 'prerender' navigation type accurately (#75)

* Add launchOption and update comments in playwright test file

* Expect 'prerender' navigationType in test assertions

* Output 'prerender' navigation type if activationStart is non-zero

---------

Co-authored-by: Andrew Hyndman <ahyndman@dropbox.com>

src/visuallyCompleteCalculator.ts

@@ -136,7 +136,9 @@ class VisuallyCompleteCalculator {
 
       const navigationType = isBfCacheRestore
         ? 'back_forward'
-        : start !== 0
+        : activationStart > 0
+        ? 'prerender'
+        : start > 0
         ? 'script'
         : getNavigationType();
 

test/e2e/prerender1/index.spec.ts

@@ -1,11 +1,25 @@
 import {test, expect} from '@playwright/test';
 
 import {FUDGE} from '../../util/constants';
-import {getEntries} from '../../util/entries';
+import {entryCountIs, getEntries} from '../../util/entries';
+
+test.use({
+  // If you run this test headless, you must run with --headless=new to enable prerender2.
+  launchOptions: {
+    args: ['--headless=new'],
+  },
+});
 
 test.describe('TTVC', () => {
-  //we had to skip this test since chromium does not support prerendering yet, hopefully in the future we can enforce it. Meanwhile you can test this changes manually by waiting a set amount before the prerender and then navigating, ttvc should be somewhere less than the delay all the way up to zero depending on how long you wait.
-  test.skip('a prerendered navigation', async ({page}) => {
+  // NOTE: At time of writing, there is a bug in chromium which prevents
+  // playwright from accessing the correct frame to run assertions after a
+  // prerendered page has been activated.
+  // These tests should be re-enabled once this issue is resolved.
+  // https://github.com/microsoft/playwright/issues/22733
+  test.skip('navigation to a partially prerendered route', async ({browserName, page}) => {
+    // neither safari nor firefox do not support page prerendering
+    test.fail(['safari', 'firefox'].includes(browserName));
+
     await page.goto(`/test/prerender1`, {
       waitUntil: 'networkidle',
     });
@@ -14,35 +28,36 @@ test.describe('TTVC', () => {
 
     await page.click('a');
 
-    await page.waitForTimeout(2000);
-
+    await entryCountIs(page, 1);
     const entries = await getEntries(page);
 
-    console.log(entries);
-
-    expect(entries.length).toBe(1);
     expect(entries[0].duration).toBeGreaterThanOrEqual(1000);
     expect(entries[0].duration).toBeLessThanOrEqual(1000 + FUDGE);
+    expect(entries[0].detail.navigationType).toBe('prerender');
   });
 
-  test.describe('TTVC', () => {
-    //we had to skip this test since chromium does not support prerendering yet, hopefully in the future we can enforce it. Meanwhile you can test this changes manually by waiting a set amount before the prerender and then navigating, ttvc should be somewhere less than the delay all the way up to zero depending on how long you wait.
-    test.skip('a prerendered navigation', async ({page}) => {
-      await page.goto(`/test/prerender1`, {
-        waitUntil: 'networkidle',
-      });
+  // NOTE: At time of writing, there is a bug in chromium which prevents
+  // playwright from accessing the correct frame to run assertions after a
+  // prerendered page has been activated.
+  // These tests should be re-enabled once this issue is resolved.
+  // https://github.com/microsoft/playwright/issues/22733
+  test.skip('navigation to a fully prerendered route', async ({browserName, page}) => {
+    // neither safari nor firefox do not support page prerendering
+    test.fail(['safari', 'firefox'].includes(browserName));
 
-      await page.waitForTimeout(2000);
+    await page.goto(`/test/prerender1`, {
+      waitUntil: 'networkidle',
+    });
 
-      await page.click('a');
+    await page.waitForTimeout(5000);
 
-      await page.waitForTimeout(2000);
+    await page.click('a');
 
-      const entries = await getEntries(page);
+    await entryCountIs(page, 1);
+    const entries = await getEntries(page);
 
-      expect(entries.length).toBe(1);
-      expect(entries[0].duration).toBeGreaterThanOrEqual(0);
-      expect(entries[0].duration).toBeLessThanOrEqual(0 + FUDGE);
-    });
+    expect(entries[0].duration).toBeGreaterThanOrEqual(0);
+    expect(entries[0].duration).toBeLessThanOrEqual(0 + FUDGE);
+    expect(entries[0].detail.navigationType).toBe('prerender');
   });
 });