Tighten up specs and extract method

lib/gitlab/alerting/alert.rb

@@ -120,15 +120,19 @@ module Gitlab
       end
 
       def parse_gitlab_alert_from_payload
+        alerts_found = matching_gitlab_alerts
+
+        return if alerts_found.blank? || alerts_found.size > 1
+
+        alerts_found.first
+      end
+
+      def matching_gitlab_alerts
         return unless metric_id || gitlab_prometheus_alert_id
 
-        alerts_found = Projects::Prometheus::AlertsFinder
+        Projects::Prometheus::AlertsFinder
           .new(project: project, metric: metric_id, id: gitlab_prometheus_alert_id)
           .execute
-
-        return if alerts_found.empty? || alerts_found.size > 1
-
-        alerts_found.first
       end
 
       def parse_title_from_payload

spec/lib/gitlab/alerting/alert_spec.rb

@@ -13,7 +13,10 @@ describe Gitlab::Alerting::Alert do
     let(:gitlab_alert_id) { gitlab_alert.id }
 
     before do
-      payload['labels'] = { 'gitlab_prometheus_alert_id' => gitlab_alert_id }
+      payload['labels'] = {
+        'gitlab_alert_id' => gitlab_alert.prometheus_metric_id.to_s,
+        'gitlab_prometheus_alert_id' => gitlab_alert_id
+      }
     end
   end
 
@@ -81,7 +84,10 @@ describe Gitlab::Alerting::Alert do
 
       context 'alert id given in params' do
         before do
-          payload['labels'] = { 'gitlab_prometheus_alert_id' => second_gitlab_alert.id }
+          payload['labels'] = {
+            'gitlab_alert_id' => gitlab_alert.prometheus_metric_id.to_s,
+            'gitlab_prometheus_alert_id' => second_gitlab_alert.id
+          }
         end
 
         it { is_expected.to eq(second_gitlab_alert) }