# Pattern Test

> Write and run pattern tests

- Skill: `commontoolsinc/pattern-test` (Agent Skill)
- Install (CLI): `npx skillmds@latest add commontoolsinc/pattern-test`
- Raw SKILL.md: https://api.skillmd.com/api/skills/commontoolsinc/pattern-test/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: commontoolsinc (https://skillmd.com/u/commontoolsinc)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/commontoolsinc/pattern-test

---


Start with the shared testing guidance in:

- `docs/common/ai/pattern-testing-guide.md`

Read that guide first. It is the canonical reference.

Run tests with:

```bash
deno task cf test <pattern>.test.tsx
```

Imports resolve from the nearest ancestor whose `deno.json(c)` declares a
package name (`packages/patterns` for repo patterns). A failure naming an import
that "escapes the program root" means the test imports from above that root —
pass `--root` naming a common ancestor of every imported file.

Keep the complete list of test entry paths for deployment. A deployed source
revision carries those tests only when each entry is supplied with a repeatable
`--test` flag:

```bash
deno task cf piece new <pattern>.tsx --test <pattern>.test.tsx ...
deno task cf piece setsrc <pattern>.tsx --test <pattern>.test.tsx --cell <piece-id> ...
```

Repeat `--test` for multiple entry files and repeat the complete flag set on
every `setsrc`. The deployment command packages and type-checks attached tests
but does not execute them, so a successful `cf test` run remains required.

When working in a Pattern Factory Build workspace, also follow
`docs/common/ai/pattern-factory-build-guide.md` (as mandated by pattern-dev). It
defines Pattern Factory's build completion gate and expected coverage shape.

For patterns that stamp timestamps or IDs, prefer deterministic assertions over
recomputing time/random values inside the test itself.

If `cf test` fails before or during assertions, treat that as pattern debugging,
not as a reason to guess at a new test shape. Before the next repair, read:

- `docs/development/debugging/README.md`

Then follow the linked gotcha or workflow for the exact error. For Cell,
Writable, or reactive-value failures, re-consult `reactivity.md` and
`new-cells.md` (as mandated by pattern-dev).

Runtime notes:

- Use the `cf` skill, or read `skills/cf/SKILL.md`, when you need CLI command
  details.
- The detailed workflow reference remains
  `docs/common/workflows/pattern-testing.md`.

## Done When

- `deno task cf test` exits 0 for every test file. A failing test is not a valid
  done state unless a concrete external, tooling, or environment blocker
  prevents further repair.
- New or changed source code has automated test coverage. PRs that introduce new
  untested lines of code will fail in CI.
- Coverage matches the testing guide's expected shape: the product contract, not
  only the happy path (first-run/default states; primary add, remove, edit,
  toggle, or submit flows; repeated actions; validation and edge-case branches
  from the spec).
- The pattern still compiles after any interface changes made to support
  testing.
- Every authored test entry is handed to deployment for attachment to the source
  revision.