openapi-mock_initial-release.md

@equinor/fusion-openapi-mock	minor

Add @equinor/fusion-openapi-mock: fakes OpenAPI 3 responses straight from a parsed spec document, so testing an API-shaped client needs no hand-written fixtures until a specific edge case needs overriding.

import { createOpenApiMock, fetchOpenApiDocument } from '@equinor/fusion-openapi-mock';

const openapi = await fetchOpenApiDocument('https://api.example.com/openapi.json');
const mock = createOpenApiMock(openapi, { seed: 42 });

const response = await mock.resolve({ method: 'GET', path: '/pets/1' });
// response.mock is already shaped like the operation's declared response schema

Highlights:

• Every operation with an operationId is faked from its declared success response schema, $refs resolved against the document — no hand-written mock data needed to get started.
• overrides (at construction) and .register(operationId, handler) (afterwards) replace the faked response for just the operations an edge case cares about.
• seed makes faked output repeatable across runs, for assertions against concrete expected values instead of expect.any(...).
• fetchOpenApiDocument(url, options?) fetches and parses a JSON or YAML spec from a URL, so there's no need to download and commit a copy that can drift out of sync.
• fields, a FieldFakerMap keyed "<ModelName>.<field>", fakes specific fields with a @faker-js/faker path string or a real function — without editing the spec itself. loadFakerMap(source) loads one from a .json/.yml/.yaml/.ts/.js sidecar file (functions require .ts/.js), or accepts an already-built map.
• No dependency on any HTTP or routing framework: resolve({ method, path, query }) returns a plain { status, mock }, so it drops into @equinor/fusion-framework-module-http's mock router, openapi-backend, Express, or a hand-rolled server equally easily.