opencode/packages/codemode/test/test262-promise.md

Test262 Promise Coverage

The Promise tests adapt Test262 at revision 250f204f23a9249ff204be2baec29600faae7b75. The upstream Promise tree contains 729 files; 459 are under the eight API directories corresponding to CodeMode's five Promise statics and three chaining methods. The executable suite currently cites 39 distinct Promise, Array, and async-function sources.

This is coverage of CodeMode's confined Promise surface, not a claim of ECMAScript or Test262 conformance. One upstream file may contain both adapted and inapplicable assertions, so a cited source means only that the represented assertions were adapted. LICENSE.test262 contains the upstream BSD terms.

Covered Surface

• Promise.all, Promise.allSettled, and Promise.race result types, ordering, sparse positions, mixed values, and rejection propagation.
• Promise.resolve value adoption and promise identity.
• Promise.reject reason preservation.
• Async-function promise creation, returned-value adoption, and throws before and after await.

The Promise PR's handwritten tests remain authoritative for tool-call concurrency, execution-scoped lifetime, cancellation, output boundaries, model-safe tool failures, unhandled-rejection diagnostics, and chaining behavior.

Exclusions

• new Promise, externally captured resolving functions, and executor semantics.
• Promise subclasses, constructors, species, realms, proxies, property descriptors, and function metadata.
• Custom thenables, poisoned then accessors, and arbitrary iterable or iterator-closing behavior.
• Promise.any, Promise.try, Promise.withResolvers, Promise.allKeyed, and Promise.allSettledKeyed.
• Exact native microtask behavior for .then, .catch, and .finally; those are exercised separately by the Promise PR's chaining tests and audit.
• Exact native unhandled-rejection timing. CodeMode drains execution-owned work and reports safe diagnostics at its execution boundary.

Observed Differences

• Promise combinators accept arrays plus CodeMode's supported spreadable collections. The model guidance currently describes arrays, so this remains a contract decision rather than conformance coverage.
• Promise.race([]) returns an actionable error instead of a permanently pending promise, which cannot usefully finish a bounded CodeMode execution.
• Promise identity is preserved, but CodeMode intentionally rejects general binary operators over Promise references; identity is tested through Map keys instead of ===.