test: Pin when/unless export reachability for airframe-rx-html migration (#526)

[xerial]

Summary

Closes #526.

The issue asked whether when / unless are actually reachable through import wvlet.uni.dom.all.* after the airframe-rx-html → uni migration, with two paths: confirm + document, or fix.

The exports already work as designed:

• wvlet/uni/dom/all.scala:155-156 exports wvlet.uni.dom.when and wvlet.uni.dom.unless.
• The existing test "conditional rendering with when" (DomElementTest.scala:90-98) already exercises that path through import wvlet.uni.dom.all.*.

This PR takes the "confirm + document" path:

1. Adds two unless regression tests so a future refactor of all.scala can't silently drop the unless export with green tests (today only when was covered).
2. Tightens the Re-export helper functions doc on all.scala to name when / unless as the airframe-rx-html migration path, so the next reader has the answer in-place.

No production code change.

Test plan

• ./sbt domTest/test — 344/344 pass (was 342, +2 unless tests).
• ./sbt scalafmtAll clean.

🤖 Generated with Claude Code

[gemini-code-assist]

Code Review

This pull request addresses issue #526 by confirming and documenting the availability of when and unless helpers within the wvlet.uni.dom.all scope, facilitating migration from airframe-rx-html. The changes include a new design document, enhanced Scaladoc for re-exports, and new regression tests. Feedback was provided to strengthen the test assertions for the unless helper by verifying the specific type and content of the rendered node, ensuring that the presence of empty nodes does not lead to false positive test results.

[gemini-code-assist]

The assertion d.modifiers.flatten.size shouldBe 1 is insufficient to verify that the conditional branch actually rendered the expected element. In this framework, DomNode.empty also occupies a slot in the modifiers list, meaning this test would pass even if unless incorrectly returned an empty node. It is better to verify the content or type of the rendered node to ensure the logic is correctly implemented.

    d.modifiers.flatten.size shouldBe 1
    d.modifiers.flatten.head shouldMatch { case e: DomElement =>
      e.name shouldBe "span"
    }

References

1. When type checking, remember that elements from a collection can be of a more specific subtype which may have additional methods not present on the base type.

[xerial]

Re: codex P2 — fixed in 50bef6e. Added example.dom.AllExportsTest in a sibling package that imports only wvlet.uni.dom.all.* and uses when / unless unqualified. If a future refactor drops the all.* re-export, this test file fails to compile — which is exactly the contract being pinned.

Kept the runtime-behavior unless tests in wvlet.uni.dom.DomElementTest, since those still exercise the renderer behavior (and the comment now makes the package-visibility caveat explicit and points at the example.dom test for the export contract).

[xerial]

/gemini review

[gemini-code-assist]

Code Review

This pull request addresses issue #526 by verifying and documenting that the when and unless helper functions are correctly re-exported and accessible via import wvlet.uni.dom.all.*. The changes include a new regression test in a separate package to ensure export visibility, additional runtime behavior tests for unless, and updated documentation in all.scala regarding the migration path from airframe-rx-html. A review comment correctly identifies that hardcoding line numbers in the plan documentation creates a maintenance burden as those references have already become outdated due to the code changes.

[gemini-code-assist]

Hardcoding specific line numbers in documentation files (e.g., all.scala:155-156) is a maintenance burden as they become outdated whenever the referenced file is modified. In this PR, the line numbers in all.scala have already shifted to 157-158. It is better to refer to the specific symbols or sections by name to ensure the documentation remains accurate over time.