Lowercase fix for "service worker" (#2729)

lighthouse-core/audits/cache-start-url.js

@@ -50,7 +50,7 @@ class CacheStartUrl extends Audit {
 
     // Now find the start_url in the cacheContents. This test is less than ideal since the Service
     // Worker can rewrite a request from the start URL to anything else in the cache, and so a TODO
-    // here would be to resolve this more completely by asking the Service Worker about the start
+    // here would be to resolve this more completely by asking the service worker about the start
     // URL. However that would also necessitate the cache contents gatherer relying on the manifest
     // gather rather than being independent of it.
     const cacheContents = artifacts.CacheContents;

lighthouse-core/audits/service-worker.js

@@ -16,8 +16,8 @@ class ServiceWorker extends Audit {
     return {
       category: 'Offline',
       name: 'service-worker',
-      description: 'Registers a Service Worker',
-      failureDescription: 'Does not register a Service Worker',
+      description: 'Registers a service worker',
+      failureDescription: 'Does not register a service worker',
       helpText: 'The service worker is the technology that enables your app to use many ' +
          'Progressive Web App features, such as offline, add to homescreen, and push ' +
          'notifications. [Learn more](https://developers.google.com/web/tools/lighthouse/audits/registered-service-worker).',

lighthouse-core/audits/webapp-install-banner.js

@@ -73,15 +73,15 @@ class WebappInstallBanner extends MultiCheckAudit {
   static assessServiceWorker(artifacts, result) {
     const hasServiceWorker = SWAudit.audit(artifacts).rawValue;
     if (!hasServiceWorker) {
-      result.failures.push('Site does not register a Service Worker');
+      result.failures.push('Site does not register a service worker');
     }
   }
 
   static assessOfflineStartUrl(artifacts, result) {
     const hasOfflineStartUrl = artifacts.StartUrl.statusCode === 200;
 
     if (!hasOfflineStartUrl) {
-      result.failures.push('Manifest start_url is not cached by a Service Worker');
+      result.failures.push('Manifest start_url is not cached by a service worker');
     }
 
     if (artifacts.StartUrl.debugString) {

lighthouse-core/test/audits/service-worker-test.js

@@ -10,8 +10,8 @@ const assert = require('assert');
 
 /* eslint-env mocha */
 
-describe('Offline: Service Worker audit', () => {
-  it('passes when given a matching Service Worker version', () => {
+describe('Offline: service worker audit', () => {
+  it('passes when given a matching service worker version', () => {
     const output = Audit.audit({
       ServiceWorker: {
         versions: [{

lighthouse-core/test/audits/webapp-install-banner-test.js

@@ -132,7 +132,7 @@ describe('PWA: webapp install banner audit', () => {
 
     return WebappInstallBannerAudit.audit(artifacts).then(result => {
       assert.strictEqual(result.rawValue, false);
-      assert.ok(result.debugString.includes('Service Worker'), result.debugString);
+      assert.ok(result.debugString.includes('service worker'), result.debugString);
       const failures = result.extendedInfo.value.failures;
       // start url will be -1 as well so failures will be 2
       assert.strictEqual(failures.length, 2, failures);

lighthouse-core/test/gather/gatherers/service-worker-test.js

@@ -11,7 +11,7 @@ const ServiceWorkerGather = require('../../../gather/gatherers/service-worker');
 const assert = require('assert');
 let serviceWorkerGatherer;
 
-describe('Service Worker gatherer', () => {
+describe('service worker gatherer', () => {
   // Reset the Gatherer before each test.
   beforeEach(() => {
     serviceWorkerGatherer = new ServiceWorkerGather();