Add timestamp columns to VSA aggregated RecordsFetcher

The aggregated version of the VSA `RecordsFetcher`, used at group level,
was missing the `start_event_timestamp` and `end_event_timestamp`
columns. As a result, such attributes were always null in the JSON
response to
`Projects::Analytics::CycleAnalytics::StagesController#records`.

Changelog: fixed

lib/gitlab/analytics/cycle_analytics/aggregated/records_fetcher.rb

@@ -38,7 +38,7 @@ def serialized_records
             strong_memoize(:serialized_records) do
               # When RecordsFetcher is used with query sourced from
               # InOperatorOptimization::QueryBuilder only columns
-              # used in ORDER BY statement would be selected by Arel.start operation
+              # used in ORDER BY statement would be selected by Arel.star operation
               selections = [stage_event_model.arel_table[Arel.star]]
               selections << duration_in_seconds.as('total_time') if params[:sort] != :duration # duration sorting already exposes this data
 
@@ -55,7 +55,9 @@ def serialized_records
                   project_path: project.path,
                   namespace_path: project.namespace.route.path,
                   author: issuable.author,
-                  total_time: record.total_time
+                  total_time: record.total_time,
+                  start_event_timestamp: record.start_event_timestamp,
+                  end_event_timestamp: record.end_event_timestamp
                 })
                 serializer.represent(attributes)
               end

spec/lib/gitlab/analytics/cycle_analytics/aggregated/records_fetcher_spec.rb

@@ -27,6 +27,26 @@
 
       expect(returned_iids).to eq(expected_issue_ids)
     end
+
+    it 'passes a hash with all expected attributes to the serializer' do
+      expected_attributes = [
+        'created_at',
+        'id',
+        'iid',
+        'title',
+        :end_event_timestamp,
+        :start_event_timestamp,
+        :total_time,
+        :author,
+        :namespace_path,
+        :project_path
+      ]
+      serializer = instance_double(records_fetcher.send(:serializer).class.name)
+      allow(records_fetcher).to receive(:serializer).and_return(serializer)
+      expect(serializer).to receive(:represent).at_least(:once).with(hash_including(*expected_attributes)).and_return({})
+
+      records_fetcher.serialized_records
+    end
   end
 
   describe '#serialized_records' do

spec/lib/gitlab/analytics/cycle_analytics/records_fetcher_spec.rb

@@ -8,15 +8,18 @@
   end
 
   let(:params) { { from: 1.year.ago, current_user: user } }
+  let(:records_fetcher) do
+    Gitlab::Analytics::CycleAnalytics::DataCollector.new(
+      stage: stage,
+      params: params
+    ).records_fetcher
+  end
 
   let_it_be(:project) { create(:project, :empty_repo) }
   let_it_be(:user) { create(:user) }
 
   subject do
-    Gitlab::Analytics::CycleAnalytics::DataCollector.new(
-      stage: stage,
-      params: params
-    ).records_fetcher.serialized_records
+    records_fetcher.serialized_records
   end
 
   describe '#serialized_records' do
@@ -28,6 +31,26 @@
       it 'returns all records' do
         expect(subject.size).to eq(2)
       end
+
+      it 'passes a hash with all expected attributes to the serializer' do
+        expected_attributes = [
+          'created_at',
+          'id',
+          'iid',
+          'title',
+          'end_event_timestamp',
+          'start_event_timestamp',
+          'total_time',
+          :author,
+          :namespace_path,
+          :project_path
+        ]
+        serializer = instance_double(records_fetcher.send(:serializer).class.name)
+        allow(records_fetcher).to receive(:serializer).and_return(serializer)
+        expect(serializer).to receive(:represent).twice.with(hash_including(*expected_attributes)).and_return({})
+
+        subject
+      end
     end
 
     describe 'for issue based stage' do