From b11cfd66b185a253fecf10ad06080ae165f32a74 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Sun, 19 Apr 2026 16:12:02 -0500 Subject: feat: adopt pairwise-tests (PICT combinatorial) + cross-reference from existing testing skills MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Forked verbatim from omkamal/pypict-claude-skill (MIT). LICENSE preserved. Renamed from `pict-test-designer` to `pairwise-tests` — technique-first naming so users invoking "pairwise" or "combinatorial" find it; PICT remains the tool under the hood. Bundle (skill-runtime only): pairwise-tests/SKILL.md (renamed, description rewritten) pairwise-tests/LICENSE (MIT, preserved) pairwise-tests/references/pict_syntax.md pairwise-tests/references/examples.md pairwise-tests/scripts/pict_helper.py (Python CLI for model gen / output fmt) pairwise-tests/scripts/README.md Upstream's repo-level docs (README, QUICKSTART, CONTRIBUTING, etc.) and `examples/` dir (ATM + gearbox walkthroughs — useful as reading, not as skill-runtime) omitted from the fork. Attribution footer added. Cross-references so /add-tests naturally routes to /pairwise-tests when warranted: - add-tests/SKILL.md Phase 2 step 8: if a function in scope has 3+ parameters each taking multiple values, surface `/pairwise-tests` to the user before proposing normal category coverage. Default continues with /add-tests; user picks pairwise explicitly. - claude-rules/testing.md: new "Combinatorial Coverage" section after the Normal/Boundary/Error categories. Explains when pairwise wins, when to skip (regulated / provably exhaustive contexts, ≤2 parameters, non- parametric testing), and points at /pairwise-tests. - languages/python/claude/rules/python-testing.md: new "Pairwise / Combinatorial for Parameter-Heavy Functions" subsection under the parametrize guidance. Explains the pytest workflow: /pairwise-tests generates the matrix, paste into pytest parametrize block, or use pypict helper directly. Mechanism note: cross-references are judgment-based — Claude reads the nudges in add-tests/testing/python-testing and acts on them when appropriate, not automatic dispatch. Craig can still invoke /pairwise-tests directly when he already knows he wants combinatorial coverage. Makefile SKILLS extended; make install symlinks /pairwise-tests globally. --- languages/python/claude/rules/python-testing.md | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'languages/python/claude/rules') diff --git a/languages/python/claude/rules/python-testing.md b/languages/python/claude/rules/python-testing.md index 6f04b7f..d2342c1 100644 --- a/languages/python/claude/rules/python-testing.md +++ b/languages/python/claude/rules/python-testing.md @@ -66,6 +66,22 @@ def test_add_item_quantity_validation(cart, quantity, valid): cart.add("SKU-1", quantity=quantity) ``` +### Pairwise / Combinatorial for Parameter-Heavy Functions + +When `@pytest.mark.parametrize` would require listing dozens of combinations +(feature flags × permissions × shipping × payment × etc.), switch to +combinatorial coverage via `/pairwise-tests`. The skill generates a minimal +matrix covering every 2-way parameter interaction — typically 80-99% fewer +cases than exhaustive, catching most combinatorial bugs. + +Workflow: invoke `/pairwise-tests` → get a PICT model + generated test matrix +→ paste the matrix into a pytest parametrize block, or use the helper to +emit directly. The `pypict` package (`pip install pypict`) handles +generation in-process. + +See `testing.md` § Combinatorial Coverage for the general rule and when +to skip. + ## Mocking Guidelines ### Mock these (external boundaries): -- cgit v1.2.3