Load commit in batches for pipelines#index

Uses `list_commits_by_oid` on the CommitService, to request the needed
commits for pipelines. These commits are needed to display the user that
created the commit and the commit title.

This includes fixes for tests failing that depended on the commit
being `nil`. However, now these are batch loaded, this doesn't happen
anymore and the commits are an instance of BatchLoader.

1 files changed, 3 insertions, 3 deletions

diff --git a/spec/serializers/pipeline_serializer_spec.rb b/spec/serializers/pipeline_serializer_spec.rb
index 88d347322a6..c38795ad1a1 100644
--- a/spec/serializers/pipeline_serializer_spec.rb
+++ b/spec/serializers/pipeline_serializer_spec.rb
@@ -1,6 +1,7 @@
 require 'spec_helper'
 
 describe PipelineSerializer do
+  set(:project) { create(:project, :repository) }
   set(:user) { create(:user) }
 
   let(:serializer) do
@@ -16,7 +17,7 @@ describe PipelineSerializer do
       end
 
       context 'when a single object is being serialized' do
-        let(:resource) { create(:ci_empty_pipeline) }
+        let(:resource) { create(:ci_empty_pipeline, project: project) }
 
         it 'serializers the pipeline object' do
           expect(subject[:id]).to eq resource.id
@@ -24,7 +25,7 @@ describe PipelineSerializer do
       end
 
       context 'when multiple objects are being serialized' do
-        let(:resource) { create_list(:ci_pipeline, 2) }
+        let(:resource) { create_list(:ci_pipeline, 2, project: project) }
 
         it 'serializers the array of pipelines' do
           expect(subject).not_to be_empty
@@ -100,7 +101,6 @@ describe PipelineSerializer do
 
     context 'number of queries' do
       let(:resource) { Ci::Pipeline.all }
-      let(:project) { create(:project) }
 
       before do
         # Since RequestStore.active? is true we have to allow the