Add a spec for rate limiting pipeline schedules

app/controllers/projects/pipeline_schedules_controller.rb

@@ -45,7 +45,7 @@ class Projects::PipelineSchedulesController < Projects::ApplicationController
     limiter = ::Gitlab::ActionRateLimiter.new(action: 'play_pipeline_schedule')
 
     if limiter.throttled?(throttle_key, 1)
-      flash[:notice] = 'You cannot play this scheduled pipeline at the moment. Please wait a minute.'
+      flash[:alert] = 'You cannot play this scheduled pipeline at the moment. Please wait a minute.'
       return redirect_to pipeline_schedules_path(@project)
     end
 
@@ -53,7 +53,7 @@ class Projects::PipelineSchedulesController < Projects::ApplicationController
 
     flash[:notice] =
       if job_id
-        "Successfully scheduled a pipeline to run. Go to the <a href=\"#{project_pipelines_path(@project)}\">Pipelines page</a> for details".html_safe
+        "Successfully scheduled a pipeline to run. Go to the <a href=\"#{project_pipelines_path(@project)}\">Pipelines page</a> for details.".html_safe
       else
         'Unable to schedule a pipeline to run immediately'
       end

spec/controllers/projects/pipeline_schedules_controller_spec.rb

@@ -385,6 +385,16 @@ describe Projects::PipelineSchedulesController do
         expect(flash[:notice]).to start_with 'Successfully scheduled a pipeline to run'
         expect(response).to have_gitlab_http_status(302)
       end
+
+      it 'prevents users from scheduling the same pipeline repeatedly' do
+        2.times do
+          post :play, namespace_id: project.namespace.to_param, project_id: project, id: pipeline_schedule.id
+        end
+
+        expect(flash.to_a.size).to eq(2)
+        expect(flash[:alert]).to eq 'You cannot play this scheduled pipeline at the moment. Please wait a minute.'
+        expect(response).to have_gitlab_http_status(302)
+      end
     end
 
     context 'when a developer attempts to schedule a protected ref' do