ci(aio): verify that the Lighthouse PWA score remains above a threshold

aio/scripts/deploy-preview.sh

@@ -6,14 +6,17 @@ set +x -eu -o pipefail
 
 INPUT_DIR=dist/
 OUTPUT_FILE=/tmp/snapshot.tar.gz
-AIO_BUILDS_HOST=https://ngbuilds.io
-UPLOAD_URL=$AIO_BUILDS_HOST/create-build/$TRAVIS_PULL_REQUEST/$TRAVIS_PULL_REQUEST_SHA
+AIO_BUILDS_DOMAIN=ngbuilds.io
+UPLOAD_URL=https://$AIO_BUILDS_DOMAIN/create-build/$TRAVIS_PULL_REQUEST/$TRAVIS_PULL_REQUEST_SHA
+DEPLOYED_URL=https://pr$TRAVIS_PULL_REQUEST-$TRAVIS_PULL_REQUEST_SHA.$AIO_BUILDS_DOMAIN
 
 cd "`dirname $0`/.."
 
-yarn run build
+# Build the app
+yarn build
 tar --create --gzip --directory "$INPUT_DIR" --file "$OUTPUT_FILE" .
 
+# Deploy to staging
 exec 3>&1
 httpCode=$(
   curl --include --location --request POST --silent --write-out "\nHTTP_CODE: %{http_code}\n" \
@@ -30,4 +33,7 @@ if [ $httpCode -lt 200 ] || ([ $httpCode -ge 400 ] && [ $httpCode -ne 409 ]); th
   exit 1
 fi
 
+# Run PWA-score tests
+yarn test-pwa-score -- "$DEPLOYED_URL" "$MIN_PWA_SCORE_PREVIEW"
+
 cd -

aio/scripts/deploy-staging.sh

@@ -5,6 +5,7 @@ set +x -eu -o pipefail
 
 
 FIREBASE_PROJECT_ID=aio-staging
+DEPLOYED_URL=https://$FIREBASE_PROJECT_ID.firebaseapp.com
 
 cd "`dirname $0`/.."
 
@@ -15,4 +16,7 @@ yarn build
 firebase use "$FIREBASE_PROJECT_ID" --token "$FIREBASE_TOKEN"
 firebase deploy --message "Commit: $TRAVIS_COMMIT" --non-interactive --token "$FIREBASE_TOKEN"
 
+# Run PWA-score tests
+yarn test-pwa-score -- "$DEPLOYED_URL" "$MIN_PWA_SCORE_STAGING"
+
 cd -

aio/scripts/test-pwa-score.js

@@ -0,0 +1,106 @@
+#!/bin/env node
+
+/**
+ * Usage:
+ *   node scripts/test-pwa-score [<url> [<min-score>]]
+ *
+ * Defaults:
+ *   url: http://localhost:4200
+ *   minScore: 90
+ *
+ * (Ignores HTTPS-related audits, when run for HTTP URL.)
+ */
+
+// Imports
+const lighthouse = require('lighthouse');
+const ChromeLauncher = require('lighthouse/lighthouse-cli/chrome-launcher').ChromeLauncher;
+const Printer = require('lighthouse/lighthouse-cli/printer');
+const config = require('lighthouse/lighthouse-core/config/default.json');
+
+// Constants
+const FLAGS = {output: 'json'};
+
+// Specify the path to Chrome on Travis
+if (process.env.TRAVIS) {
+  process.env.LIGHTHOUSE_CHROMIUM_PATH = process.env.CHROME_BIN;
+}
+
+// Run
+_main(process.argv.slice(2));
+
+// Functions - Definitions
+function _main(args) {
+  const {url, minScore} = parseInput(args);
+  const isOnHttp = /^http:/.test(url);
+
+  console.log(`Running PWA audit for '${url}'...`);
+
+  if (isOnHttp) {
+    ignoreHttpsAudits(config.aggregations);
+  }
+
+  launchChromeAndRunLighthouse(url, FLAGS, config).
+    then(getScore).
+    then(score => evaluateScore(minScore, score)).
+    catch(onError);
+}
+
+function evaluateScore(expectedScore, actualScore) {
+  console.log('Lighthouse PWA score:');
+  console.log(`  - Expected: ${expectedScore} / 100 (or higher)`);
+  console.log(`  - Actual:   ${actualScore} / 100`);
+
+  if (actualScore < expectedScore) {
+    throw new Error(`PWA score is too low. (${actualScore} < ${expectedScore})`);
+  }
+}
+
+function getScore(results) {
+  const scoredAggregations = results.aggregations.filter(a => a.scored);
+  const total = scoredAggregations.reduce((sum, a) => sum + a.total, 0);
+
+  return Math.round((total / scoredAggregations.length) * 100);
+}
+
+function ignoreHttpsAudits(aggregations) {
+  const httpsAudits = [
+    'is-on-https',
+    'redirects-http'
+  ];
+
+  console.info(`Ignoring HTTPS-related audits (${httpsAudits.join(', ')})...`);
+
+  aggregations.forEach(aggregation =>
+    aggregation.items.forEach(item =>
+      httpsAudits.map(key => item.audits[key]).forEach(audit =>
+        // Ugly hack to ignore HTTPS-related audits (i.e. simulate them passing).
+        // Only meant for use during development.
+        audit && (audit.expectedValue = !audit.expectedValue))));
+}
+
+function launchChromeAndRunLighthouse(url, flags, config) {
+  const launcher = new ChromeLauncher({autoSelectChrome: true});
+
+  return launcher.run().
+    then(() => lighthouse(url, flags, config)).
+    then(results => launcher.kill().then(() => results)).
+    catch(err => launcher.kill().then(() => { throw err; }, () => { throw err; }));
+}
+
+function onError(err) {
+  console.error(err);
+  process.exit(1);
+}
+
+function parseInput(args) {
+  const url = args[0];
+  const minScore = Number(args[1]);
+
+  if (!url) {
+    onError('Invalid arguments: <URL> not specified.');
+  } else if (isNaN(minScore)) {
+    onError('Invalid arguments: <MIN_SCORE> not specified or not a number.');
+  }
+
+  return {url, minScore};
+}