每次我使用rails test运行测试时，Spring都会在新实例中启动。见下文：
$ spring status
Spring is running:
56604 spring server | sample_app | started 9 mins ago
56804 spring app | sample_app | started 7 mins ago | test mode
$ rails test
Running via Spring preloader in process 57248
Started with run options --seed 27813
5/5: [=====================================================================================================================] 100% Time: 00:00:00, Time: 00:00:00
Finished in 0.58059s
5 tests, 9 assertions, 0 failures, 0 errors, 0 skips
有什么方法可以防止这种情况改善测试套件的性能吗？