Agent skill · software engineering · remotion-dev
writing-tests
Guidance for explicitly requested new tests and for updating or reviewing existing tests in the Remotion repository.
Why this skill is useful
Provides specific guidelines for writing integration tests in the Remotion repository that the AI wouldn't reliably generate on its own.
What it needs
About 8k tokens when loaded. Last updated 2026-08-06. 55,698 stars on the source repository.
What this skill does
Writing Tests Apply this skill when the user explicitly requests new tests or when existing tests, fixtures, or snapshots need updates for feature work, bug fixes, refactors, or PR preparation. Do not add new tests, including new test cases in existing files, unless the user explicitly requests them. A request to review tests does not authorize changing them. The purpose of a test is confidence that a workflow or contract works for a Studio user, CLI user, package consumer, or renderer consumer. Test the feature at the widest stable boundary that gives useful confidence. Prefer one complete integration workflow; use focused unit tests for genuinely complex logic and E2E tests for critical cross-process workflows. Test count, assertion count, file count, and coverage percentage are not quality metrics. One rendered frame, final artifact, or persisted-source assertion can give more confidence than many narrow unit assertions. A test that stays green when the feature is disconnected is not useful primary coverage. For a user-facing or cross-layer feature, a private helper unit test must not be the only coverage. Choose the boundary before writing the test Answer these questions first: 1. What failure would a user or public API consumer notice? 2. What is the widest stable boundary that can reproduce it economically? 3. Is there an existing integration or E2E workflow that can be extended? 4. Would the proposed test fail if the feature entry point stopped calling the tested helper? 5. Which edge cases, if any, still justify focused unit tests? Test type is determined by the boundary, not the directory or runner. A Bun test can be an integration test, while a Playwright test can still be coupled to implementation details. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills remotion-dev/writing-tests