Avoid recompiling std when tests change in std::net

[tesuji]

I moved ui tests to their own files.
It's best when review commit by commit.

I could squash them all if requested.
r? @KodrAus

[KodrAus]

Thanks @lzutao!

It looks like we don’t have a really consistent approach to organizing tests here in std, is there anything special about these ones to move them into separate files or is the plan to work through other modules and do the same thing?

[tesuji]

I am modifying things in #75110 . It is kind of painful when I only change tests to investigate fall outs in that PR
but std is recompiled.

[tesuji]

@KodrAus Should I open an MCP on compiler team repo to enforce tests module in separate file?

[bors]

☔ The latest upstream changes (presumably #75019) made this pull request unmergeable. Please resolve the merge conflicts.

[KodrAus]

Should I open an MCP on compiler team repo to enforce tests module in separate file?

I wasn't actually aware that moving #[cfg(test)] modules into a separate file could save recompiling the main crate when only that test file changes. If that's the case then it seems like that would be worth doing! We could try re-organize more of std's tests to resemble the way they're done in core?

[tesuji]

Reopened the proposal in #75979.