fix for builds with no start date and spec

app/serializers/entity_date_helper.rb

@@ -2,6 +2,8 @@ module EntityDateHelper
   include ActionView::Helpers::DateHelper
 
   def interval_in_words(diff)
+    return 'not started' unless diff
+
     "#{distance_of_time_in_words(Time.now, diff)} ago"
   end
 

spec/serializers/analytics_build_entity_spec.rb

@@ -7,7 +7,9 @@ describe AnalyticsBuildEntity do
 
   context 'build with an author' do
     let(:user) { create(:user) }
-    let(:build) { create(:ci_build, author: user, started_at: 2.hours.ago, finished_at: 1.hour.ago) }
+    let(:started_at) { 2.hours.ago }
+    let(:finished_at) { 1.hour.ago }
+    let(:build) { create(:ci_build, author: user, started_at: started_at, finished_at: finished_at) }
 
     subject { entity.as_json }
 
@@ -31,5 +33,32 @@ describe AnalyticsBuildEntity do
     it 'contains the duration' do
       expect(subject[:total_time]).to eq(hours: 1 )
     end
+
+    context 'no started at or finished at date' do
+      let(:started_at) { nil }
+      let(:finished_at) { nil }
+
+      it 'does not blow up' do
+        expect{ subject[:date] }.not_to raise_error
+      end
+
+      it ''
+    end
+
+    context 'no started at date' do
+      let(:started_at) { nil }
+
+      it 'does not blow up' do
+        expect{ subject[:date] }.not_to raise_error
+      end
+    end
+
+    context 'no finished at date' do
+      let(:finished_at) { nil }
+
+      it 'does not blow up' do
+        expect{ subject[:date] }.not_to raise_error
+      end
+    end
   end
 end