Replace set with let_it_in in spec/workers

Removes usage of `set` in specs

spec/workers/detect_repository_languages_worker_spec.rb

@@ -3,7 +3,7 @@
 require 'spec_helper'
 
 describe DetectRepositoryLanguagesWorker do
-  set(:project) { create(:project) }
+  let_it_be(:project) { create(:project) }
 
   subject { described_class.new }
 

spec/workers/expire_build_instance_artifacts_worker_spec.rb

@@ -31,7 +31,7 @@ describe ExpireBuildInstanceArtifactsWorker do
     end
 
     context 'with not yet expired artifacts' do
-      set(:build) do
+      let_it_be(:build) do
         create(:ci_build, :artifacts, artifacts_expire_at: Time.now + 7.days)
       end
 

spec/workers/expire_job_cache_worker_spec.rb

@@ -3,7 +3,7 @@
 require 'spec_helper'
 
 describe ExpireJobCacheWorker do
-  set(:pipeline) { create(:ci_empty_pipeline) }
+  let_it_be(:pipeline) { create(:ci_empty_pipeline) }
   let(:project) { pipeline.project }
 
   describe '#perform' do

spec/workers/mail_scheduler/notification_service_worker_spec.rb

@@ -6,7 +6,7 @@ describe MailScheduler::NotificationServiceWorker do
   let(:worker) { described_class.new }
   let(:method) { 'new_key' }
 
-  set(:key) { create(:personal_key) }
+  let_it_be(:key) { create(:personal_key) }
 
   def serialize(*args)
     ActiveJob::Arguments.serialize(args)

spec/workers/pipeline_schedule_worker_spec.rb

@@ -7,8 +7,8 @@ describe PipelineScheduleWorker do
 
   subject { described_class.new.perform }
 
-  set(:project) { create(:project, :repository) }
-  set(:user) { create(:user) }
+  let_it_be(:project) { create(:project, :repository) }
+  let_it_be(:user) { create(:user) }
 
   let!(:pipeline_schedule) do
     create(:ci_pipeline_schedule, :nightly, project: project, owner: user)

spec/workers/remote_mirror_notification_worker_spec.rb

@@ -3,8 +3,8 @@
 require 'spec_helper'
 
 describe RemoteMirrorNotificationWorker, :mailer do
-  set(:project) { create(:project, :repository, :remote_mirror) }
-  set(:mirror) { project.remote_mirrors.first }
+  let_it_be(:project) { create(:project, :repository, :remote_mirror) }
+  let_it_be(:mirror) { project.remote_mirrors.first }
 
   describe '#execute' do
     it 'calls NotificationService#remote_mirror_update_failed when the mirror exists' do

spec/workers/run_pipeline_schedule_worker_spec.rb

@@ -4,9 +4,9 @@ require 'spec_helper'
 
 describe RunPipelineScheduleWorker do
   describe '#perform' do
-    set(:project) { create(:project) }
-    set(:user) { create(:user) }
-    set(:pipeline_schedule) { create(:ci_pipeline_schedule, :nightly, project: project ) }
+    let_it_be(:project) { create(:project) }
+    let_it_be(:user) { create(:user) }
+    let_it_be(:pipeline_schedule) { create(:ci_pipeline_schedule, :nightly, project: project ) }
     let(:worker) { described_class.new }
 
     context 'when a project not found' do

spec/workers/update_external_pull_requests_worker_spec.rb

@@ -4,8 +4,8 @@ require 'spec_helper'
 
 describe UpdateExternalPullRequestsWorker do
   describe '#perform' do
-    set(:project) { create(:project, import_source: 'tanuki/repository') }
-    set(:user) { create(:user) }
+    let_it_be(:project) { create(:project, import_source: 'tanuki/repository') }
+    let_it_be(:user) { create(:user) }
     let(:worker) { described_class.new }
 
     before do