# Agent instructions
## Testing
Do not write tests that check the existence or the correctness of support
files: READMEs, LICENSE and NOTICE files, Markdown files and other docs,
changelogs, and configuration files (Cargo manifests, CI workflows,
`rust-toolchain.toml`, `rustfmt.toml`, and similar). Tests exercise the
library, its examples and its scripts' behavior, not the repository's
documentation or configuration.
## Spelling
Use American English everywhere: prose, code comments and doc comments,
documentation, identifiers (types, functions, fields, variables, modules,
constants, test names), error and log messages, JavaScript, file names, and
commit, pull-request, and changelog text. Write `color`, `neighbor`,
`behavior`, `canceled`, `signaled`, `labeled`, `modeled`, `center`, `gray`,
`favor`, `honor`, `artifact`, and `-ize`/`-ization` (`initialize`,
`normalize`, `serialize`, `optimize`, `materialize`), not the British forms.
`cancellation` is already the American spelling.
This applies to names taken from the codec and container specifications as
well: where the ITU-T, AOM, or Matroska documents spell a syntax element or
element name the British way, the code still uses the American spelling, as in
`color_primaries`, `separate_color_plane_flag`, and the WebM `Color` element.
Keep a British spelling only where it is not ours to change or is quoted on
purpose: verbatim third-party license and notice text, the names of external
APIs and web standards (such as the HTML `aria-labelledby` attribute), and the
old names a changelog entry lists when it records a rename.