Merge branch 'add-pipeline-metrics-worker' into 'master'

Add Pipeline metrics worker

## What does this MR do?
Creating a new Merge Request metrics is time consuming, because we need to access repository.

This makes this operation asynchronous, thus non-blocking for updating pipeline.

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !6896

1 files changed, 9 insertions, 18 deletions

diff --git a/spec/models/ci/pipeline_spec.rb b/spec/models/ci/pipeline_spec.rb
index 550a890797e..163c0b5c516 100644
--- a/spec/models/ci/pipeline_spec.rb
+++ b/spec/models/ci/pipeline_spec.rb
@@ -187,33 +187,24 @@ describe Ci::Pipeline, models: true do
       end
     end
 
-    describe "merge request metrics" do
+    describe 'merge request metrics' do
       let(:project) { FactoryGirl.create :project }
       let(:pipeline) { FactoryGirl.create(:ci_empty_pipeline, status: 'created', project: project, ref: 'master', sha: project.repository.commit('master').id) }
       let!(:merge_request) { create(:merge_request, source_project: project, source_branch: pipeline.ref) }
 
-      context 'when transitioning to running' do
-        it 'records the build start time' do
-          time = Time.now
-          Timecop.freeze(time) { build.run }
-
-          expect(merge_request.reload.metrics.latest_build_started_at).to be_within(1.second).of(time)
-        end
-
-        it 'clears the build end time' do
-          build.run
+      before do
+        expect(PipelineMetricsWorker).to receive(:perform_async).with(pipeline.id)
+      end
 
-          expect(merge_request.reload.metrics.latest_build_finished_at).to be_nil
+      context 'when transitioning to running' do
+        it 'schedules metrics workers' do
+          pipeline.run
         end
       end
 
       context 'when transitioning to success' do
-        it 'records the build end time' do
-          build.run
-          time = Time.now
-          Timecop.freeze(time) { build.success }
-
-          expect(merge_request.reload.metrics.latest_build_finished_at).to be_within(1.second).of(time)
+        it 'schedules metrics workers' do
+          pipeline.succeed
         end
       end
     end