Background

Some crates have grown long inline #[cfg(test)] mod tests { ... } blocks at the bottom of source files (e.g. crates/package-manager/src/install.rs). The markdown guides in this repo direct test code into dedicated files / module hierarchies once the inline block becomes hard to scan, but the convention is not yet enforced and has drifted in places.

Ask

• Audit each crate for inline mod tests blocks longer than the size threshold the guides recommend.
• For each one over the threshold, move the tests into either a sibling tests.rs module file or a tests/ integration directory, whichever the guides prefer for the test's scope.
• Update the guides if the threshold/style needs to be made more explicit so this doesn't drift again.

This is purely a code-organization change, no behavior change. Should be done as small per-crate PRs.