add CloudWatch Annotation

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

@@ -2,6 +2,7 @@
 ///<amd-dependency path="test/specs/helpers" name="helpers" />
 
 import {describe, beforeEach, it, sinon, expect, angularMocks} from 'test/lib/common';
+import moment = require('moment');
 
 declare var helpers: any;
 
@@ -189,4 +190,50 @@ describe('CloudWatchDatasource', function() {
     });
   });
 
+  describe('When performing annotationQuery', function() {
+    var annotation = {
+      region: 'us-east-1',
+      namespace: 'AWS/EC2',
+      metricName: 'CPUUtilization',
+      dimensions: 'InstanceId=i-12345678'
+    };
+    var alarmResponse = {
+      MetricAlarms: [
+        {
+          AlarmName: 'test_alarm_name'
+        }
+      ]
+    };
+    var historyResponse = {
+      AlarmHistoryItems: [
+        {
+          Timestamp: '2015-01-01T00:00:00.000Z',
+          HistoryItemType: 'StateUpdate',
+          AlarmName: 'test_alarm_name',
+          HistoryData: '{}',
+          HistorySummary: 'test_history_summary'
+        }
+      ]
+    };
+    beforeEach(function() {
+      ctx.backendSrv.datasourceRequest = function(params) {
+        switch (params.data.action) {
+        case 'DescribeAlarmsForMetric':
+          return ctx.$q.when({data: alarmResponse});
+          break;
+        case 'DescribeAlarmHistory':
+          return ctx.$q.when({data: historyResponse});
+          break;
+        }
+      };
+    });
+    it('should return annotation list', function(done) {
+      ctx.ds.annotationQuery(annotation, {from: moment(1443438674760), to: moment(1443460274760)}).then(function(result) {
+        expect(result[0].title).to.be('test_alarm_name');
+        expect(result[0].text).to.be('test_history_summary');
+        done();
+      });
+      ctx.$rootScope.$apply();
+    });
+  });
 });