test code usage

[Ruanyx1823]

Location (URL)

https://github.com/rust-lang/rust/pull/143924/files#diff-b65385768c85c61859d87ba71e9d4a3c914df3c53bff0990e23d659ee9c0c196

Summary

Hello, I haven't found the documentation on how to use these test cases. How should I test?

[lqd]

This PR hasn't landed yet, so you should ask there. Closing this issue as it's not actionable until then.