Add basic specs for new merge requests pipelines API

spec/controllers/projects/merge_requests_controller_spec.rb

@@ -22,22 +22,34 @@ describe Projects::MergeRequestsController do
       render_views
 
       let(:fork_project) { create(:forked_project_with_submodules) }
+      before { fork_project.team << [user, :master] }
 
-      before do
-        fork_project.team << [user, :master]
+      context 'when rendering HTML response' do
+        it 'renders new merge request widget template' do
+          submit_new_merge_request
+
+          expect(response).to be_success
+        end
+      end
+
+      context 'when rendering JSON response' do
+        it 'renders JSON including serialized pipelines' do
+          submit_new_merge_request(format: :json)
+
+          expect(json_response).to have_key('pipelines')
+          expect(response).to be_ok
+        end
+      end
     end
 
-      it 'renders it' do
+    def submit_new_merge_request(format: :html)
       get :new,
           namespace_id: fork_project.namespace.to_param,
           project_id: fork_project.to_param,
           merge_request: {
             source_branch: 'remove-submodule',
-              target_branch: 'master'
-            }
-
-        expect(response).to be_success
-      end
+            target_branch: 'master' },
+          format: format
     end
   end