@n8n-probe/mock-http

@n8n-probe/mock-http

HTTP mocking for n8n nodes that call external APIs, built on MSW for the fast in-process tier and testcontainers + WireMock for the opt-in real-server tier.

import {
  setupMswForTest,
  mockApi,
  presets,
  createMockHttpExecuteFunctions,
} from '@n8n-probe/mock-http';
import { MyHttpNode } from '../nodes/MyHttpNode/MyHttpNode.node';

const server = setupMswForTest();

it('reads a user from the API', async () => {
  server.use(...mockApi().get('https://api.example.com/users/1').reply(200, { id: 1 }).handlers());

  const ctx = createMockHttpExecuteFunctions({
    input: [{ json: {} }],
    params: { url: 'https://api.example.com/users/1' },
  });
  const out = await new MyHttpNode().execute.call(ctx);

  expect(out[0][0].json).toEqual({ id: 1 });
});

MSW tier (part of pnpm test)

• setupMswForTest(handlers?) — one shared server per test file, wired to beforeAll / afterEach / afterAll. An unmatched request fails the test (onUnhandledRequest: 'error') instead of hanging or hitting the network. Returns the server for per-case server.use(...).
• mockApi() — fluent handler builder: mockApi().get(url).reply(200, body).post(url2).reply(201).handlers(). body: string → text, ArrayBuffer / typed array → binary, anything else → JSON, omitted → empty.
• presets — ready-made handlers for the failure modes node authors get wrong: rateLimited(path) (429 + Retry-After: 1), timeout(path) (never settles — set a bounded request timeout), flakyThenSuccess(path, n, body?) (503 for the first n calls, then 200).
• createMockHttpExecuteFunctions(options?) — @n8n-probe/core's mock context with helpers.httpRequest wired to a real axios client, so a node's outbound calls are actually intercepted. Same options as createMockExecuteFunctions.
• performHttpRequest(node, options) — the axios-backed helpers.httpRequest stand-in on its own. Maps the common IHttpRequestOptions fields; a non-2xx response (unless ignoreHttpStatusErrors) or a transport failure is thrown as NodeApiError.

WireMock tier (opt-in, needs Docker — pnpm test:e2e:full)

• startWireMock({ mappingsDir?, image? }) — boots wiremock/wiremock via testcontainers and returns { baseUrl, stop() }. Use it for reusable stub mappings, latency and fault injection, or cross-language contract stubs. testcontainers is an optional peer dependency. Always await stop().

MSW vs WireMock: MSW is in-process, millisecond-fast and needs no Docker — use it for the default suite. WireMock is a real HTTP server in a container — use it when the stubs must be shared across teams or languages, or when you need realistic network behaviour (latency, connection resets, proxying, record & replay).

Part of n8n-probe. Not affiliated with n8n GmbH.