📚 Split backend testing memory and link from testing skill

Extract the backend Testing section from backend/core into a dedicated
backend/testing memory, following the pattern of common, frontend, and
exporter. Update the testing skill and root testing memory to point at
the new location, and add exporter/testing to the skill's required
reading list.

AI-assisted-by: deepseek-v4-flash

.opencode/skills/testing/SKILL.md

@@ -34,7 +34,8 @@ Before writing any test, read:
 2. Module-specific testing memory for the affected module:
    - `mem:common/testing` — CLJC unit tests
    - `mem:frontend/testing` — CLJS unit tests, Playwright E2E
-   - `mem:backend/core` — JVM clojure.test conventions
+   - `mem:backend/testing` — JVM clojure.test conventions
+   - `mem:exporter/testing` — exporter unit tests
 
 ## Key Rules
 

.serena/memories/backend/core.md

@@ -102,9 +102,5 @@ misleading linter/compiler output. See `mem:scripts/paren-repair`.
 
 ## Testing
 
-IMPORTANT: all CLI commands must be executed from the `backend/` subdirectory. JVM tests are invoked directly via `clojure -M:dev:test` — there is no pnpm wrapper. If you need to filter output, tee to a temp file first: `clojure -M:dev:test 2>&1 | tee /tmp/penpot-test-output.txt`. See `mem:testing` for execution discipline.
+Backend test commands, coverage rules, and conventions: `mem:backend/testing`.
-
+Cross-cutting testing principles, anti-patterns, and verification checklist: `mem:testing`.
-* **Coverage:** If code is added or modified in `src/`, corresponding tests in `test/backend_tests/` must be added or updated.
-* **Isolated run:** `clojure -M:dev:test --focus backend-tests.my-ns-test` for a specific test namespace.
-* **Regression run:** `clojure -M:dev:test` to ensure no regressions in related functional areas.
-* **Principles:** Cross-cutting testing principles, anti-patterns, and verification checklist: `mem:testing`.

.serena/memories/backend/testing.md

@@ -0,0 +1,11 @@
+# Backend Testing
+
+JVM `clojure.test` (kaocha runner) under `backend/test/backend_tests/`.
+
+- READ `mem:testing` FIRST — it defines the execution discipline (no piping, tee to file, preferred commands) that applies to all JVM test runs.
+- All CLI commands must be executed from the `backend/` subdirectory.
+- Tests are invoked directly via `clojure -M:dev:test` (kaocha) — there is no pnpm wrapper. Kaocha auto-discovers test namespaces, so no runner registration is needed.
+- Coverage: if code is added or modified in `src/`, corresponding tests in `test/backend_tests/` must be added or updated.
+- Isolated run: `clojure -M:dev:test --focus backend-tests.my-ns-test` for a specific test namespace, or `clojure -M:dev:test --focus backend-tests.my-ns-test/my-test-var` for a specific test var.
+- Regression run: `clojure -M:dev:test` to ensure no regressions in related functional areas.
+- If you need to filter output, tee to a temp file first: `clojure -M:dev:test 2>&1 | tee /tmp/penpot-test-output.txt`.

.serena/memories/testing.md

@@ -13,7 +13,7 @@ and helpers, consult:
   builders, production-path change helpers
 - `mem:frontend/testing` — CLJS unit tests, Playwright E2E integration tests,
   live browser verification via nREPL
-- Backend — JVM `clojure.test` under `backend/test/`; see `mem:backend/core`
+- `mem:backend/testing` — JVM `clojure.test` under `backend/test/`
 
 ## When to Use