core/symbols-in-sibling — exports must show up in the sibling

Correlation across two files: every symbol a module exports must be referenced in its partner file (typically the test). Catches untested exports.

What it catches

An exported function, class, or const that the sibling test never mentions — a sign it’s untested. It parses the module to find its exports, then checks they appear in the partner. This is the parser-as-library family: it reasons across files, not just within one line.

Config

rules:
  - id: exports-are-tested
    use: core/symbols-in-sibling
    on: "src/domain/**/*.ts"
    sibling: "{dir}/{name}.test.ts"   # where the exports must be referenced
    message: "Each exported symbol must be referenced in its test. Red → green."
Field What it does
on Glob(s) for the modules to check.
sibling The partner whose text must mention each export — same {dir}/{name}/{base}/{path} templating as core/sibling-exists.
message The reason, shown on a block. 
// user.ts          export function getUser(){…}  export function delUser(){…}
// user.test.ts     test(getUser…)                 // delUser never referenced
                                                    ✗ blocked: 'delUser' untested

Reference, not assertion. It checks the export is mentioned in the partner — a cheap, fast proxy for “is it tested”, not a coverage tool. For true coverage, reach for a core/tool-gate.