Refactor compliance entity spec using let_it_be

ee/spec/serializers/merge_request_compliance_entity_spec.rb

@@ -7,10 +7,10 @@ RSpec.describe MergeRequestComplianceEntity do
 
   let_it_be(:project) { create(:project) }
   let_it_be(:user) { create(:user) }
-  let(:merge_request) { create(:merge_request, state: :merged) }
+  let_it_be(:merge_request) { create(:merge_request, :merged) }
 
   let(:request) { double('request', current_user: user, project: project) }
-  let(:entity) { described_class.new(merge_request, request: request) }
+  let(:entity) { described_class.new(merge_request.reload, request: request) }
 
   describe '.as_json' do
     subject { entity.as_json }
@@ -35,9 +35,9 @@ RSpec.describe MergeRequestComplianceEntity do
 
     describe 'with an approver' do
       let_it_be(:approver) { create(:user) }
-      let!(:approval) { create :approval, merge_request: merge_request, user: approver }
+      let_it_be(:approval) { create :approval, merge_request: merge_request, user: approver }
 
-      before do
+      before_all do
         project.add_developer(approver)
       end
 
@@ -51,7 +51,7 @@ RSpec.describe MergeRequestComplianceEntity do
     end
 
     describe 'with a head pipeline' do
-      let!(:pipeline) { create(:ci_empty_pipeline, status: :success, project: project, head_pipeline_of: merge_request) }
+      let_it_be(:pipeline) { create(:ci_empty_pipeline, status: :success, project: project, head_pipeline_of: merge_request) }
 
       describe 'and the user cannot read the pipeline' do
         it 'does not include pipeline status attribute' do