README

Shared cross-language conformance fixtures for the Fancy suite.

One contract, N implementations, and a single fixture table that every implementation asserts in its own CI, on every push — so "parity" is a test result rather than a claim.

npm install --save-dev @particle-academy/fancy-conformance
composer require --dev particle-academy/fancy-conformance

For a language with no package yet, every release attaches a plain fancy-conformance-<version>.tar.gz containing just the fixtures — no npm, no Composer, no JavaScript toolchain.

The policy

N implementations of one contract are acceptable if and only if a shared fixture table is asserted by every implementation, in that implementation's own CI, on every push.

Anything less is not parity. It is a transliteration with a README.

Why this exists

Most Fancy server capabilities ship as a matched PHP + Node pair, so the same feature works behind the same UI whichever backend runs it. Keeping two implementations honest by hand does not work, and we have the receipts:

mcp-relay-client ships four single-file clients. All four were hand-transliterated in one commit and none was touched again while the TypeScript source took four substantive changes. Result: 9 divergences, including a wrong default relay path in all four. CI never compiled the Go one, never imported the Python one, never executed the shell one.
holy-sheet's PHP↔JS parity suite — the strongest guarantee in that pair — never ran in CI. describe.skipIf(!HAS_PHP) skipped silently and the workflow installed Node only. It also hard-coded ../../holy-sheet/src/, so it worked in exactly one directory layout.
dark-slide's harness had the same shape, with the same green-on-zero-coverage outcome.
The FeatureSource contract is byte-identical in two packages and maintained by hand. It survives only because TypeScript's structural typing does the checking — a mechanism that does not exist in Rust or Go.

The counter-example is in the same org and is the whole argument. satisfiesRange is also a three-way duplicate — fancy-ui-cli, fancy-flow, fancy-flow-php — and it has not drifted. The only thing it does differently: each repo carries the identical case table in its own CI, the PHP one literally titled "matches the TypeScript satisfiesRange, clause for clause."

Same organisation, same problem shape, opposite outcome. The variable is the shared table. That table is now suites/shared/satisfies-range/, promoted here verbatim.

What is in here

Suite	Cases	Pins
`shared/satisfies-range`	17	Minimal semver range matching, including two rows that deliberately disagree with standard semver
`shared/decimal`	18	Float formatting, numeric-string coercion, and money rounding
`shared/strings`	8	Inline-markdown segmentation across CJK, emoji, combining marks and accented Latin

Every case carries an id, a title, the suite version it arrived in, and — where it exists to catch something specific — a notes field saying what.

Using it

import { runTable, formatSummary } from "@particle-academy/fancy-conformance";
import { satisfiesRange } from "../src/marketplace/manifest";

const summary = runTable(
  "shared/satisfies-range",
  (c) => satisfiesRange(c.input.version, c.input.range),
  { language: "node" },
);

console.log(formatSummary(summary));   // always — see rule 3
if (!summary.ok) process.exit(1);

use ParticleAcademy\Conformance\Conformance;

$summary = Conformance::runTable(
    'shared/satisfies-range',
    fn (array $c) => NodeManifest::satisfiesRange($c['input']['version'], $c['input']['range']),
);

echo Conformance::formatSummary($summary), "\n";
exit($summary['ok'] ? 0 : 1);

Full runner contract, including the subprocess CLI for suites that emit documents rather than return values: runners/README.md.

The four rules for a consuming repo

Each one is traceable to a suite in this org that reported green while covering nothing.

Run the suite on every push and PR. Not nightly, not at release.
A missing toolchain is a FAILURE, not a skip. skipIf(!HAS_PHP) returning green is the specific mechanism that hid two-way drift for months. If the suite cannot run, the job goes red.
Print the summary unconditionally, including every skip and its reason. A bare "3 skipped" reads identically to full coverage at a glance.
Print and assert the pinned suite version, so "we're on an old fixture set" is visible rather than inferred.

Skipping a case

skip is the only sanctioned way not to run a case, it is keyed by language, and the reason may not be empty — an empty one is a load error, in both loaders, asserted on both sides:

{
  "id": "0014-round-negative-half",
  "skip": { "go": "no decimal type yet — tracking Particle-Academy/…#12" }
}

Every runner prints every skip. A silent skip is what turned two existing parity suites into decoration, so it is not representable here.

This repository holds itself to the same standard

It ships two loaders for one fixture format, which is itself a duplicated contract. So:

Each language's test suite proves that language reads the fixtures correctly.
npm run cross-check runs both loaders over the same suites and requires identical verdicts case by case — the claim neither suite can make about itself. It is a required CI job, and it exits non-zero if zero cases were compared.
tests/discrimination.test.ts runs deliberately wrong implementations and requires each to fail the exact cases that exist to catch it. A golden table that every plausible implementation passes is decoration; this is what proves it is not.

Adding a case

A new case lands here first, red, then in each implementation. Where an implementation cannot pass it yet, it gets a skip with a real reason and a tracking issue — and that skip appears in that repo's CI log every run until it is gone.

Never renumber an id. Ids appear in changelogs and in other repos' skip lists.

Versioning

VERSION is the fixture set's own semver, and the publish workflow refuses a tag unless the tag, VERSION and package.json all agree. Every implementation pins a version and states it in its README; raising the pin is a deliberate act with a changelog entry.

Pre-1.0, breaking changes land in minor releases.

License

MIT

particle-academy / fancy-conformance

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