Improve pipelines API specs related to special parameters

spec/requests/api/pipelines_spec.rb

@@ -232,20 +232,26 @@ describe API::Pipelines do
 
         context 'when order_by and sort are specified' do
           context 'when order_by user_id' do
-            before { 3.times { create(:ci_pipeline, project: project, user: create(:user)) } }
+            before do
+              3.times do
+                create(:ci_pipeline, project: project, user: create(:user))
+              end
+            end
 
-            it 'sorts as user_id: :asc' do
-              get api("/projects/#{project.id}/pipelines", user), order_by: 'user_id', sort: 'asc'
+            context 'when sort parameter is valid' do
+              it 'sorts as user_id: :desc' do
+                get api("/projects/#{project.id}/pipelines", user), order_by: 'user_id', sort: 'desc'
 
                 expect(response).to have_http_status(:ok)
                 expect(response).to include_pagination_headers
                 expect(json_response).not_to be_empty
 
-              pipeline_ids = Ci::Pipeline.all.order(:user_id).map(&:id)
+                pipeline_ids = Ci::Pipeline.all.order(user_id: :desc).pluck(:id)
                 expect(json_response.map { |r| r['id'] }).to eq(pipeline_ids)
               end
+            end
 
-            context 'when sort is invalid' do
+            context 'when sort parameter is invalid' do
               it 'returns bad_request' do
                 get api("/projects/#{project.id}/pipelines", user), order_by: 'user_id', sort: 'invalid_sort'