alamb opened a new pull request, #25756: URL: https://github.com/apache/datafusion/pull/25756
## Which issue does this PR close? - Closes #. ## Rationale for this change The contributor guide already says that `sqllogictest` (`.slt`) tests and end-to-end API tests are preferred over Rust unit tests, but the guidance is buried: the rationale lives at the bottom of the `sqllogictests` section of the [testing guide](https://datafusion.apache.org/contributor-guide/testing.html#sqllogictests-tests), and the [Before Submitting a PR](https://datafusion.apache.org/contributor-guide/index.html#before-submitting-a-pr) section only says to *run* the tests, not to follow the testing guidelines. `AGENTS.md` does not mention it at all. As a result, both humans and coding agents regularly add large Rust unit tests where a few lines of `.slt` would do (see for example https://github.com/apache/datafusion/pull/25744#discussion_r4107006055). Making the guidance more visible should help keep code growth down and tests less coupled to implementation details. ## What changes are included in this PR? - `docs/source/contributor-guide/testing.md`: add a new "Choosing What Kind of Test to Write" section near the top that states the order of preference (`.slt`, then end-to-end API tests, then Rust unit tests) and the rationale (no recompile cycle, `--complete` auto-update, less code to maintain). The rationale that previously lived in the `sqllogictests` section is moved there, and that section now links to the new section and to the sqllogictest README cookbook. - `docs/source/contributor-guide/index.md`: "Before Submitting a PR" now says to follow the testing guidelines (prefer `.slt` and end-to-end API tests where possible), not just run the quick start commands. - `docs/source/contributor-guide/pr_review.md`: link the existing "prefer `.slt`" review guideline to the new section. - `AGENTS.md`: add the guidance to the "Testing" section and link the new section from "Developer Documentation", so agents creating PRs pick it up. ## What is the testing strategy for this PR? Documentation only. Ran `./ci/scripts/doc_prettier_check.sh --write --allow-dirty`. ## Are there any user-facing changes? No, contributor documentation only. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
