test(mapper): strengthen concurrency and nested-AND coverage

[shihyuho]

Summary

Strengthens two mapper tests so they actually exercise the code paths they claim to cover (WP10, findings TEST-06 and TEST-05). Test-only change — no production code touched.

• TEST-06 (concurrency). ReflectionDatabindTest.fireOnlyOnce previously ran a single-threaded pool (numberOfThreads = 1), so the AtomicBoolean CAS + CountDownLatch dedup in ReflectionDatabind.getFieldValue() was never contended and the times(1) assertion would pass even if the dedup were deleted. It now launches 32 threads held at a CyclicBarrier and released together, so multiple threads race into getFieldValue() on the same Databind instances, while still asserting the inner reflective read runs exactly once per bind.
• TEST-05 (three-level AND). NestedInNestedAnd.name was annotated @NestedSpec String name (a typo vs its OR twin's @Spec), so recursing into a String yielded null and the deepest AND level was silently absent. Changed to @Spec (mirroring NestedInNestedOr) and extended allAnd's assertions to a full three-level Conjunction tree symmetric to allOr's Disjunction tree.

TEST-03 (inherited criteria fields) is deliberately out of scope — it needs a human policy decision and is tracked separately.

Closes #182

Acceptance criteria

• ReflectionDatabindTest.fireOnlyOnce launches 32 concurrent threads held at a start barrier and released together, so multiple threads call the same ReflectionDatabind.getFieldValue() concurrently.
• For every Databind returned by ReflectionDatabind.of(...), the test asserts the inner getFieldValue(object, field) read is invoked exactly once (times(1)) despite the concurrent access.
• The strengthened concurrency test passes deterministically with no production-code change.
• NestedInNestedAnd.name is annotated @Spec (matching NestedInNestedOr.name).
• allAnd asserts a three-level Conjunction tree: top-level Conjunction of size 2 (Equals + nested Conjunction), nested Conjunction of size 2 (Equals + deepest Conjunction), deepest Conjunction of size 1 containing an Equals.
• allAnd's repository result still returns exactly matt.
• mvn test (mapper module) passes.

Testing

mvn test run on JDK 17 — full reactor green: specification-mapper and specification-mapper-starter both SUCCESS. The two affected classes: ReflectionDatabindTest (1 test) and NestedSpecificationResolverTest (5 tests) pass.

[shihyuho]

APPROVE (advisory) — reviewed all 9 axes, no must-fix

Non-blocking (4)

• Optional · Spec conformance — mapper/src/test/java/tw/com/softleader/data/jpa/spec/ReflectionDatabindTest.java:56 — Closes #182 will auto-close the issue while TEST-06's second clause (a bind whose reflective read throws) is neither implemented nor declared out of scope.
• Nit · Correctness — mapper/src/test/java/tw/com/softleader/data/jpa/spec/ReflectionDatabindTest.java:67 — the worker-thread throw new RuntimeException(e) lands in a discarded Future, so fireOnlyOnce stays green even if every loser thread blows up.
• Nit · Correctness — mapper/src/test/java/tw/com/softleader/data/jpa/spec/ReflectionDatabindTest.java:73 — startBarrier.await() and done.await() are unbounded, so a regression in the very latch machinery this test guards would hang the build instead of failing it.
• Nit · Test coverage — mapper/src/test/java/tw/com/softleader/data/jpa/spec/NestedSpecificationResolverTest.java:395 — flipping NestedInNestedAnd.name to @Spec removes the suite's only coverage of NestedSpecificationResolver's null-collapse branch.

Coverage & checks

Axis	Status
Correctness	2 findings
Spec conformance	1 finding
Scope	clean — every hunk traced to TEST-06/TEST-05 of the linked issue; only the two test files touched
Convention	clean — checked the base-ref CLAUDE.md / AGENTS.md / CONTRIBUTING.md; AGENTS.md's only rule (commit hygiene) is CI-enforced and lands on no changed line
Security	clean — test-only; no secrets or string-built queries introduced, specs still constructed through the typed Criteria API
Readability	clean — the latch→done rename disambiguates the two synchronizers; depth2 matches the allOr/mix idiom already in the file
Architecture	clean — NestedInNestedAnd now mirrors NestedInNestedOr; the assertion navigation is byte-identical to the established pattern
Performance	clean — production sources re-fetched at the head SHA and confirmed unchanged; 32 threads costs single-digit ms
Test coverage	1 finding

• Verified — all 4 checks green: commits, pr-title, continuous-integration/jenkins/branch, continuous-integration/jenkins/pr-merge (read via gh pr checks, never run locally)
• Out-of-band — re-fetched ReflectionDatabind, NestedSpecificationResolver and SpecMapper at the head SHA to confirm no production line changed · traced ThreadPoolExecutor core-thread behaviour to rule out a CyclicBarrier(32) deadlock · confirmed Mockito's invocation recording is synchronized, so the 32-thread verify is race-free

🤖 Reviewed by Claude Opus 4.8

(self-review — same account; GitHub records this as event=COMMENT with no badge, so the verdict above is advisory.)