[Discover] Add functional tests for defaultRoute setting (#189801)

- Follow up for https://github.com/elastic/kibana/issues/189184

## Summary

Adding more tests.

test/functional/apps/discover/group8/_default_route.ts

@@ -0,0 +1,74 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import expect from '@kbn/expect';
+import { FtrProviderContext } from '../ftr_provider_context';
+
+export default function ({ getService, getPageObjects }: FtrProviderContext) {
+  const esArchiver = getService('esArchiver');
+  const PageObjects = getPageObjects([
+    'common',
+    'home',
+    'settings',
+    'discover',
+    'timePicker',
+    'header',
+  ]);
+  const kibanaServer = getService('kibanaServer');
+  const security = getService('security');
+  const retry = getService('retry');
+  const deployment = getService('deployment');
+  const browser = getService('browser');
+  const filterBar = getService('filterBar');
+  const queryBar = getService('queryBar');
+
+  describe('discover as defaultRoute', function () {
+    before(async function () {
+      await security.testUser.setRoles(['kibana_admin', 'test_logstash_reader']);
+      await kibanaServer.importExport.load('test/functional/fixtures/kbn_archiver/discover');
+      await esArchiver.loadIfNeeded('test/functional/fixtures/es_archiver/logstash_functional');
+      await kibanaServer.uiSettings.replace({ defaultIndex: 'logstash-*' });
+      await PageObjects.timePicker.setDefaultAbsoluteRangeViaUiSettings();
+    });
+
+    after(async () => {
+      await kibanaServer.importExport.unload('test/functional/fixtures/kbn_archiver/discover');
+      await esArchiver.unload('test/functional/fixtures/es_archiver/logstash_functional');
+      await kibanaServer.uiSettings.replace({});
+      await kibanaServer.savedObjects.cleanStandardList();
+    });
+
+    it('can use a saved search as defaultRoute', async function () {
+      await kibanaServer.uiSettings.update({
+        defaultRoute: '/app/discover#/view/ab12e3c0-f231-11e6-9486-733b1ac9221a',
+      });
+      await browser.navigateTo(deployment.getHostPort());
+      await PageObjects.header.waitUntilLoadingHasFinished();
+      await PageObjects.discover.waitUntilSearchingHasFinished();
+      await retry.try(async () => {
+        expect(await PageObjects.discover.getCurrentQueryName()).to.be('A Saved Search');
+        expect(await PageObjects.discover.getHitCount()).to.be('14,004');
+      });
+    });
+
+    it('can use a URL with filters as defaultRoute', async function () {
+      await kibanaServer.uiSettings.update({
+        defaultRoute:
+          "/app/discover#/?_g=(filters:!(),refreshInterval:(pause:!t,value:60000),time:(from:'2015-09-19T06:31:44.000Z',to:'2015-09-23T18:31:44.000Z'))&_a=(columns:!(extension,host),dataSource:(dataViewId:'logstash-*',type:dataView),filters:!(('$state':(store:appState),meta:(alias:!n,disabled:!f,field:extension.raw,index:'logstash-*',key:extension.raw,negate:!f,params:(query:jpg),type:phrase),query:(match_phrase:(extension.raw:jpg)))),hideChart:!f,interval:auto,query:(language:lucene,query:media),sort:!(!('@timestamp',desc)))",
+      });
+      await browser.navigateTo(deployment.getHostPort());
+      await PageObjects.header.waitUntilLoadingHasFinished();
+      await PageObjects.discover.waitUntilSearchingHasFinished();
+      await retry.try(async () => {
+        expect(await filterBar.hasFilter('extension.raw', 'jpg')).to.be(true);
+        expect(await queryBar.getQueryString()).to.be('media');
+        expect(await PageObjects.discover.getHitCount()).to.be('9,109');
+      });
+    });
+  });
+}

test/functional/apps/discover/group8/index.ts

@@ -20,6 +20,7 @@ export default function ({ getService, loadTestFile }: FtrProviderContext) {
       await esArchiver.unload('test/functional/fixtures/es_archiver/logstash_functional');
     });
 
+    loadTestFile(require.resolve('./_default_route'));
     loadTestFile(require.resolve('./_hide_announcements'));
   });
 }