Improve pipeline size for query limit test

The pipeline was quite meagre in both stages and the number of groups.
This has been improved. Performance is not yet optimal, but to limit
this from sliding further this slippery slope, a hard limit has been
set.

spec/controllers/projects/pipelines_controller_spec.rb

@@ -38,7 +38,7 @@ describe Projects::PipelinesController do
   end
 
   describe 'GET show JSON' do
-    let!(:pipeline) { create(:ci_pipeline_with_one_job, project: project) }
+    let(:pipeline) { create(:ci_pipeline_with_one_job, project: project) }
 
     it 'returns the pipeline' do
       get_pipeline_json
@@ -49,20 +49,48 @@ describe Projects::PipelinesController do
       expect(json_response['details']).to have_key 'stages'
     end
 
-    context 'when the pipeline has multiple jobs' do
+    context 'when the pipeline has multiple stages and groups' do
+      before do
+        RequestStore.begin!
+
+        create_build('build', 0, 'build')
+        create_build('test', 1, 'rspec 0')
+        create_build('deploy', 2, 'production')
+        create_build('post deploy', 3, 'pages 0')
+      end
+
+      after do
+        RequestStore.end!
+        RequestStore.clear!
+      end
+
+      let(:project) { create(:project) }
+      let(:pipeline) do
+        create(:ci_empty_pipeline, project: project, user: user, sha: project.commit.id)
+      end
+
       it 'does not perform N + 1 queries' do
         control_count = ActiveRecord::QueryRecorder.new { get_pipeline_json }.count
 
-        create(:ci_build, pipeline: pipeline)
+        create_build('test', 1, 'rspec 1')
+        create_build('test', 1, 'spinach 0')
+        create_build('test', 1, 'spinach 1')
+        create_build('test', 1, 'audit')
+        create_build('post deploy', 3, 'pages 1')
+        create_build('post deploy', 3, 'pages 2')
 
-        # The plus 2 is needed to group and sort
-        expect { get_pipeline_json }.not_to exceed_query_limit(control_count + 2)
+        new_count = ActiveRecord::QueryRecorder.new { get_pipeline_json }.count
+        expect(new_count).to be_within(12).of(control_count)
       end
     end
 
     def get_pipeline_json
       get :show, namespace_id: project.namespace, project_id: project, id: pipeline, format: :json
     end
+
+    def create_build(stage, stage_idx, name)
+      create(:ci_build, pipeline: pipeline, stage: stage, stage_idx: stage_idx, name: name)
+    end
   end
 
   describe 'GET stages.json' do