Use `let_it_be` for create_service_spec

spec/services/branches/create_service_spec.rb

@@ -3,30 +3,27 @@
 require 'spec_helper'
 
 describe Branches::CreateService do
-  let(:user) { create(:user) }
-
   subject(:service) { described_class.new(project, user) }
 
+  let_it_be(:project) { create(:project_empty_repo) }
+  let_it_be(:user) { create(:user) }
+
   describe '#execute' do
     context 'when repository is empty' do
-      let(:project) { create(:project_empty_repo) }
-
       it 'creates master branch' do
         service.execute('my-feature', 'master')
 
         expect(project.repository.branch_exists?('master')).to be_truthy
       end
 
-      it 'creates my-feature branch' do
-        service.execute('my-feature', 'master')
+      it 'creates another-feature branch' do
+        service.execute('another-feature', 'master')
 
-        expect(project.repository.branch_exists?('my-feature')).to be_truthy
+        expect(project.repository.branch_exists?('another-feature')).to be_truthy
       end
     end
 
     context 'when branch already exists' do
-      let(:project) { create(:project_empty_repo) }
-
       it 'returns an error' do
         result = service.execute('master', 'master')
 
@@ -36,14 +33,12 @@ describe Branches::CreateService do
     end
 
     context 'when incorrect reference is provided' do
-      let(:project) { create(:project_empty_repo) }
-
       before do
         allow(project.repository).to receive(:add_branch).and_return(false)
       end
 
-      it 'returns an error with reference name' do
-        result = service.execute('my-feature', 'unknown')
+      it 'returns an error with a reference name' do
+        result = service.execute('new-feature', 'unknown')
 
         expect(result[:status]).to eq(:error)
         expect(result[:message]).to eq('Invalid reference name: unknown')