Add test for Repository#after_sync

spec/models/repository_spec.rb

@@ -1972,6 +1972,16 @@ describe Repository, models: true do
     end
   end
 
+  describe '#after_sync' do
+    it 'expires repository cache' do
+      expect(repository).to receive(:expire_all_method_caches)
+      expect(repository).to receive(:expire_branch_cache)
+      expect(repository).to receive(:expire_content_cache)
+
+      repository.after_sync
+    end
+  end
+
   def create_remote_branch(remote_name, branch_name, target)
     rugged = repository.rugged
     rugged.references.create("refs/remotes/#{remote_name}/#{branch_name}", target.id)