misc: puppeteer script to test a page from devtools

lighthouse-core/scripts/pptr-run-devtools.js

@@ -0,0 +1,110 @@
+'use strict';
+
+const puppeteer = require('puppeteer');
+const fs = require('fs');
+
+/** @typedef {{result?: {value?: string, objectId?: number}, exceptionDetails?: object}} ProtocolResponse */
+
+/**
+ * https://source.chromium.org/chromium/chromium/src/+/master:third_party/devtools-frontend/src/front_end/test_runner/TestRunner.js;l=170;drc=f59e6de269f4f50bca824f8ca678d5906c7d3dc8
+ * @param {Record<string, function>} receiver
+ * @param {string} methodName
+ * @param {function} override
+ */
+function addSniffer(receiver, methodName, override) {
+  const original = receiver[methodName];
+  if (typeof original !== 'function') {
+    throw new Error('Cannot find method to override: ' + methodName);
+  }
+
+  receiver[methodName] = function() {
+    let result;
+    try {
+      // eslint-disable-next-line prefer-rest-params
+      result = original.apply(this, arguments);
+    } finally {
+      receiver[methodName] = original;
+    }
+    // In case of exception the override won't be called.
+    try {
+      // eslint-disable-next-line prefer-rest-params
+      Array.prototype.push.call(arguments, result);
+      // eslint-disable-next-line prefer-rest-params
+      override.apply(this, arguments);
+    } catch (e) {
+      throw new Error('Exception in overriden method \'' + methodName + '\': ' + e);
+    }
+    return result;
+  };
+}
+
+const sniffLhr = `
+new Promise(resolve => {
+  (${addSniffer.toString()})(
+    UI.panels.lighthouse.__proto__,
+    '_buildReportUI',
+    (lhr, artifacts) => resolve(JSON.stringify(lhr))
+  );
+});
+`;
+
+const startLighthouse = `
+(() => {
+  UI.ViewManager.instance().showView('lighthouse');
+  UI.panels.lighthouse.contentElement.querySelector('button').click();
+})()
+`;
+
+async function run() {
+  const browser = await puppeteer.launch({
+    executablePath: process.env.CHROME_PATH,
+    devtools: true,
+  });
+  const page = await browser.newPage();
+
+  // Cut off JS for initial page navigation.
+  // This step is unnecessary for every page I tried except https://cnn.com.
+  await page.setJavaScriptEnabled(false);
+
+  await page.goto(process.argv[2]);
+  const targets = await browser.targets();
+  const inspectorTarget = targets.filter(t => t.url().includes('devtools'))[1];
+  if (!inspectorTarget) throw new Error('No inspector found.');
+
+  // Enable JS for actual LH test.
+  await page.setJavaScriptEnabled(true);
+
+  const session = await inspectorTarget.createCDPSession();
+  await session.send('Runtime.enable');
+
+  /** @type {ProtocolResponse|undefined} */
+  let startLHResponse;
+  while (!startLHResponse || startLHResponse.exceptionDetails) {
+    startLHResponse = await session.send('Runtime.evaluate', {expression: startLighthouse})
+      .catch(err => err);
+    if (startLHResponse && !startLHResponse.exceptionDetails) break;
+  }
+
+  /** @type {ProtocolResponse} */
+  const snifferAddedResponse = await session.send('Runtime.evaluate', {expression: sniffLhr})
+    .catch(err => err);
+  if (!snifferAddedResponse.result || !snifferAddedResponse.result.objectId) {
+    throw new Error('Problem creating LHR sniffer.');
+  }
+
+  /** @type {ProtocolResponse} */
+  const remoteLhrResponse = await session.send('Runtime.awaitPromise', {
+    promiseObjectId: snifferAddedResponse.result.objectId,
+  }).catch(err => err);
+  if (!remoteLhrResponse.result || !remoteLhrResponse.result.value) {
+    throw new Error('Problem sniffing LHR.');
+  }
+
+  fs.writeFileSync('latest-run/lhr.json', remoteLhrResponse.result.value);
+
+  await session.send('Runtime.disable');
+
+  await page.close();
+  await browser.close();
+}
+run();

package.json

@@ -72,7 +72,7 @@
     "update:test-devtools": "bash lighthouse-core/test/chromium-web-tests/test-locally.sh --reset-results",
     "test-devtools": "bash lighthouse-core/test/chromium-web-tests/test-locally.sh",
     "open-devtools": "bash lighthouse-core/scripts/open-devtools.sh",
-    "run-devtools": "bash lighthouse-core/test/chromium-web-tests/test-page-devtools.sh",
+    "run-devtools": "node lighthouse-core/scripts/pptr-run-devtools.js",
     "diff:sample-json": "yarn i18n:checks && bash lighthouse-core/scripts/assert-golden-lhr-unchanged.sh",
     "computeBenchmarkIndex": "./lighthouse-core/scripts/benchmark.js",
     "minify-latest-run": "./lighthouse-core/scripts/lantern/minify-trace.js ./latest-run/defaultPass.trace.json ./latest-run/defaultPass.trace.min.json && ./lighthouse-core/scripts/lantern/minify-devtoolslog.js ./latest-run/defaultPass.devtoolslog.json ./latest-run/defaultPass.devtoolslog.min.json",