Add mock to test files

public/app/plugins/datasource/cloudwatch/specs/datasource.jest.ts

 import '../datasource';
-//import { describe, beforeEach, it, expect, angularMocks } from 'test/lib/common';
-import { TemplateSrvStub, jestTimeSrvStub } from 'test/specs/helpers';
+import { TemplateSrvStub } from 'test/specs/helpers';
 import CloudWatchDatasource from '../datasource';
 import 'app/features/dashboard/time_srv';
+import * as dateMath from 'app/core/utils/datemath';
 
 describe('CloudWatchDatasource', function() {
   let instanceSettings = {
     jsonData: { defaultRegion: 'us-east-1', access: 'proxy' },
   };
   let templateSrv = new TemplateSrvStub();
-  let timeSrv = new jestTimeSrvStub();
+
+  let timeSrv = {
+    time: { from: 'now-1h', to: 'now' },
+    timeRange: jest.fn(() => {
+      return {
+        from: dateMath.parse(timeSrv.time.from, false),
+        to: dateMath.parse(timeSrv.time.to, true),
+      };
+    }),
+  };
   let backendSrv = {};
   let ctx = <any>{
     backendSrv,

public/app/plugins/datasource/mysql/specs/datasource.jest.ts

-//import { describe, beforeEach, it, expect, angularMocks } from 'test/lib/common';
 import moment from 'moment';
-import { TemplateSrvStub } from 'test/specs/helpers';
 import { MysqlDatasource } from '../datasource';
 import { CustomVariable } from 'app/features/templating/custom_variable';
 
 describe('MySQLDatasource', function() {
   let instanceSettings = { name: 'mysql' };
   let backendSrv = {};
-  let templateSrv = new TemplateSrvStub();
+  let templateSrv = {
+    replace: jest.fn(text => text),
+  };
+
   let ctx = <any>{
     backendSrv,
   };

public/app/plugins/datasource/postgres/specs/datasource.jest.ts

 import moment from 'moment';
 import { PostgresDatasource } from '../datasource';
 import { CustomVariable } from 'app/features/templating/custom_variable';
-import { TemplateSrvStub } from 'test/specs/helpers';
 
 describe('PostgreSQLDatasource', function() {
   let instanceSettings = { name: 'postgresql' };
 
   let backendSrv = {};
-  let templateSrv = new TemplateSrvStub();
+  let templateSrv = {
+    replace: jest.fn(text => text),
+  };
   let ctx = <any>{
     backendSrv,
   };

public/test/specs/helpers.ts

@@ -195,24 +195,6 @@ export function TemplateSrvStub() {
   };
 }
 
-export function jestTimeSrvStub() {
-  this.init = jest.fn();
-  this.time = { from: 'now-1h', to: 'now' };
-  this.timeRange = jest.fn(parse => {
-    if (parse === false) {
-      return this.time;
-    }
-    return {
-      from: dateMath.parse(this.time.from, false),
-      to: dateMath.parse(this.time.to, true),
-    };
-  });
-  this.replace = jest.fn(target => target);
-  this.setTime = jest.fn(time => {
-    this.time = time;
-  });
-}
-
 var allDeps = {
   ContextSrvStub,
   TemplateSrvStub,