Expose merge request entity for pipelines

Add preload

Fix

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Write tests

test only postgresql

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add more test
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Improve wording

Add changelog

Fix

3 files changed, 112 insertions, 0 deletions

diff --git a/spec/serializers/merge_request_for_pipeline_entity_spec.rb b/spec/serializers/merge_request_for_pipeline_entity_spec.rb
new file mode 100644
index 00000000000..e49b45bc7d7
--- /dev/null
+++ b/spec/serializers/merge_request_for_pipeline_entity_spec.rb
@@ -0,0 +1,29 @@
+require 'spec_helper'
+
+describe MergeRequestForPipelineEntity do
+  let(:project) { create(:project, :repository) }
+  let(:user) { create(:user) }
+  let(:request) { EntityRequest.new(project: project) }
+  let(:merge_request) { create(:merge_request, target_project: project, source_project: project) }
+  let(:presenter) { MergeRequestPresenter.new(merge_request, current_user: user) }
+
+  let(:entity) do
+    described_class.new(presenter, request: request)
+  end
+
+  before do
+    project.add_developer(user)
+  end
+
+  context 'as json' do
+    subject { entity.as_json }
+
+    it 'exposes needed attributes' do
+      expect(subject).to include(
+        :iid, :path, :title,
+        :source_branch, :source_branch_path,
+        :target_branch, :target_branch_path
+      )
+    end
+  end
+end
diff --git a/spec/serializers/pipeline_entity_spec.rb b/spec/serializers/pipeline_entity_spec.rb
index 774486dcb6d..11040862129 100644
--- a/spec/serializers/pipeline_entity_spec.rb
+++ b/spec/serializers/pipeline_entity_spec.rb
@@ -1,6 +1,8 @@
 require 'spec_helper'
 
 describe PipelineEntity do
+  include Gitlab::Routing
+
   set(:user) { create(:user) }
   let(:request) { double('request') }
 
@@ -128,5 +130,48 @@ describe PipelineEntity do
           .to eq 'CI/CD YAML configuration error!'
       end
     end
+
+    context 'when pipeline is detached merge request pipeline' do
+      let(:merge_request) { create(:merge_request, :with_merge_request_pipeline) }
+      let(:project) { merge_request.target_project }
+      let(:pipeline) { merge_request.merge_request_pipelines.first }
+
+      it 'makes detached flag true' do
+        expect(subject[:flags][:detached]).to be_truthy
+      end
+
+      context 'when user is a developer' do
+        before do
+          project.add_developer(user)
+        end
+
+        it 'has merge request information' do
+          expect(subject[:merge_request][:iid]).to eq(merge_request.iid)
+
+          expect(project_merge_request_path(project, merge_request))
+            .to include(subject[:merge_request][:path])
+
+          expect(subject[:merge_request][:title]).to eq(merge_request.title)
+
+          expect(subject[:merge_request][:source_branch])
+            .to eq(merge_request.source_branch)
+
+          expect(project_branch_path(project, merge_request.source_branch))
+            .to include(subject[:merge_request][:source_branch_path])
+
+          expect(subject[:merge_request][:target_branch])
+            .to eq(merge_request.target_branch)
+
+          expect(project_branch_path(project, merge_request.target_branch))
+            .to include(subject[:merge_request][:target_branch_path])
+        end
+      end
+
+      context 'when user is an external user' do
+        it 'has no merge request information' do
+          expect(subject[:merge_request]).to be_nil
+        end
+      end
+    end
   end
 end
diff --git a/spec/serializers/pipeline_serializer_spec.rb b/spec/serializers/pipeline_serializer_spec.rb
index 2bdcb2a45f6..a21487938a0 100644
--- a/spec/serializers/pipeline_serializer_spec.rb
+++ b/spec/serializers/pipeline_serializer_spec.rb
@@ -97,6 +97,44 @@ describe PipelineSerializer do
       end
     end
 
+    context 'when there are pipelines for merge requests' do
+      let(:resource) { Ci::Pipeline.all }
+
+      let!(:merge_request_1) do
+        create(:merge_request,
+          :with_merge_request_pipeline,
+          target_project: project,
+          target_branch: 'master',
+          source_project: project,
+          source_branch: 'feature-1')
+      end
+
+      let!(:merge_request_2) do
+        create(:merge_request,
+          :with_merge_request_pipeline,
+          target_project: project,
+          target_branch: 'master',
+          source_project: project,
+          source_branch: 'feature-2')
+      end
+
+      before do
+        project.add_developer(user)
+      end
+
+      it 'includes merge requests information' do
+        expect(subject.all? { |entry| entry[:merge_request].present? }).to be_truthy
+      end
+
+      it 'preloads related merge requests', :postgresql do
+        recorded = ActiveRecord::QueryRecorder.new { subject }
+
+        expect(recorded.log)
+          .to include("SELECT \"merge_requests\".* FROM \"merge_requests\" " \
+                      "WHERE \"merge_requests\".\"id\" IN (#{merge_request_1.id}, #{merge_request_2.id})")
+      end
+    end
+
     describe 'number of queries when preloaded' do
       subject { serializer.represent(resource, preload: true) }
       let(:resource) { Ci::Pipeline.all }