[Discover] Context unskip date nanos functional tests (#73781)

* Use _source value of timestamp for search_after since ES allows this now

* Unskip functional tests

* Remove unused convertIsoToNanosAsStr
# Conflicts:
#	src/plugins/discover/public/application/angular/context/api/utils/get_es_query_search_after.ts
#	test/functional/apps/context/_date_nanos_custom_timestamp.js

src/plugins/discover/public/application/angular/context/api/utils/date_conversion.ts

@@ -31,15 +31,6 @@ export function extractNanos(timeFieldValue: string = ''): string {
   return fractionSeconds.length !== 9 ? fractionSeconds.padEnd(9, '0') : fractionSeconds;
 }
 
-/**
- * extract the nanoseconds as string of a given ISO formatted timestamp
- */
-export function convertIsoToNanosAsStr(isoValue: string): string {
-  const nanos = extractNanos(isoValue);
-  const millis = convertIsoToMillis(isoValue);
-  return `${millis}${nanos.substr(3, 6)}`;
-}
-
 /**
  * convert an iso formatted string to number of milliseconds since
  * 1970-01-01T00:00:00.000Z

src/plugins/discover/public/application/angular/context/api/utils/get_es_query_search_after.ts

@@ -16,7 +16,6 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-import { convertIsoToNanosAsStr } from './date_conversion';
 import { SurrDocType, EsHitRecordList, EsHitRecord } from '../context';
 
 export type EsQuerySearchAfter = [string | number, string | number];
@@ -38,15 +37,10 @@ export function getEsQuerySearchAfter(
     // already surrounding docs -> first or last record  is used
     const afterTimeRecIdx = type === 'successors' && documents.length ? documents.length - 1 : 0;
     const afterTimeDoc = documents[afterTimeRecIdx];
-    const afterTimeValue = nanoSeconds
-      ? convertIsoToNanosAsStr(afterTimeDoc._source[timeFieldName])
-      : afterTimeDoc.sort[0];
+    const afterTimeValue = nanoSeconds ? afterTimeDoc._source[timeFieldName] : afterTimeDoc.sort[0];
     return [afterTimeValue, afterTimeDoc.sort[1]];
   }
   // if data_nanos adapt timestamp value for sorting, since numeric value was rounded by browser
   // ES search_after also works when number is provided as string
-  return [
-    nanoSeconds ? convertIsoToNanosAsStr(anchor._source[timeFieldName]) : anchor.sort[0],
-    anchor.sort[1],
-  ];
+  return [nanoSeconds ? anchor._source[timeFieldName] : anchor.sort[0], anchor.sort[1]];
 }

test/functional/apps/context/_date_nanos.js

@@ -30,8 +30,7 @@ export default function ({ getService, getPageObjects }) {
   const PageObjects = getPageObjects(['common', 'context', 'timePicker', 'discover']);
   const esArchiver = getService('esArchiver');
 
-  // FLAKY/FAILING ES PROMOTION: https://github.com/elastic/kibana/issues/58815
-  describe.skip('context view for date_nanos', () => {
+  describe('context view for date_nanos', () => {
     before(async function () {
       await security.testUser.setRoles(['kibana_admin', 'kibana_date_nanos']);
       await esArchiver.loadIfNeeded('date_nanos');

test/functional/apps/context/_date_nanos_custom_timestamp.js

@@ -0,0 +1,60 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import expect from '@kbn/expect';
+
+const TEST_INDEX_PATTERN = 'date_nanos_custom_timestamp';
+const TEST_DEFAULT_CONTEXT_SIZE = 1;
+const TEST_STEP_SIZE = 3;
+
+export default function ({ getService, getPageObjects }) {
+  const kibanaServer = getService('kibanaServer');
+  const docTable = getService('docTable');
+  const security = getService('security');
+  const PageObjects = getPageObjects(['common', 'context', 'timePicker', 'discover']);
+  const esArchiver = getService('esArchiver');
+
+  describe('context view for date_nanos with custom timestamp', () => {
+    before(async function () {
+      await security.testUser.setRoles(['kibana_admin', 'kibana_date_nanos_custom']);
+      await esArchiver.loadIfNeeded('date_nanos_custom');
+      await kibanaServer.uiSettings.replace({ defaultIndex: TEST_INDEX_PATTERN });
+      await kibanaServer.uiSettings.update({
+        'context:defaultSize': `${TEST_DEFAULT_CONTEXT_SIZE}`,
+        'context:step': `${TEST_STEP_SIZE}`,
+      });
+    });
+
+    it('displays predessors - anchor - successors in right order ', async function () {
+      await PageObjects.context.navigateTo(TEST_INDEX_PATTERN, '1');
+      const actualRowsText = await docTable.getRowsText();
+      const expectedRowsText = [
+        'Oct 21, 2019 @ 08:30:04.828733000 -',
+        'Oct 21, 2019 @ 00:30:04.828740000 -',
+        'Oct 21, 2019 @ 00:30:04.828723000 -',
+      ];
+      expect(actualRowsText).to.eql(expectedRowsText);
+    });
+
+    after(async function () {
+      await security.testUser.restoreDefaults();
+      await esArchiver.unload('date_nanos_custom');
+    });
+  });
+}