# Testing

> Use when writing, running, or debugging tests in the Gutenberg repository — JavaScript unit tests (Jest), PHP tests (PHPUnit), or end-to-end tests (Playwright).

- Skill: `wordpress/testing` (Agent Skill, multi-file: 4 files)
- Install (CLI): `npx skillmds add wordpress/testing`
- Raw SKILL.md: https://api.skillmd.com/api/skills/wordpress/testing/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: WordPress (https://skillmd.com/u/wordpress)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/wordpress/testing

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# Testing

## Plan the tests with the author first

Before writing any test bodies, draft the test names — behavior from the user's perspective, one behavior per case (see [Describing tests](../../../docs/contributors/code/testing-overview.md#describing-tests)) — and confirm the list with the author. Every proposed case must trace to the behavior being added or changed; do not pad the list with adjacent or unrelated coverage. If working unattended, put the proposed list in your summary for review instead.

## Never make a failing test pass by weakening it

No loosened assertions, no added waits or timeouts, no skipped cases without saying so. Diagnose the root cause, or report the failure honestly.

## Never make a failing test pass by changing the production code unless the production code is the source of a bug

The e2e test passing is not the final task success criteria. The core goal is to verify that the production code works as expected.

## By test type

-   **JavaScript unit and integration tests (Jest)**: read [references/jest.md](references/jest.md).
-   **PHP tests (PHPUnit)**: read [references/php.md](references/php.md).
-   **E2e tests (Playwright)**: read [references/e2e.md](references/e2e.md).