@Xiaohan5349, when you submit your project there is no automated testing done.
As per the project instructions, when you fork the sample page the test suite is there.
If you code locally, the instructions also provide you with the CDN link for the test suite.
You can run the test suite yourself to ensure that all tests are passing prior to submitting your project.
When you submit your project, keep the test suite in your project.
If you’d like to have others look over your project and provide you feedback you can open a topic in the #project-feedback subforum. Be sure to include a link to your project when you do.