@justscale/testing

Test utilities for JustScale: a createTestKit() harness that spawns one or more app instances with lifecycle auto-drain, plus DI mocks and spy helpers built on node:test.

Install

pnpm add -D @justscale/testing

Usage

import { test } from 'node:test';
import { createTestKit } from '@justscale/testing';

test('user service', async (t) => {
  const kit = createTestKit(t);

  const app = await kit.spawn(builder =>
    builder.register(UserRepository, myInMemoryRepo),
  );

  const result = await app.service(UserService).findAll();
  assert.ok(result.length > 0);
});

createTestKit(t) registers afterEach automatically and drains all lifecycle handles (timers, locks, channels) on teardown — no manual cleanup required.

API

• createTestKit(t) — primary harness.
  • kit.spawn(builderFn) — single in-process app.
  • kit.spawnHttp(builderFn, opts?) — app with real HTTP listener; returns typed client for controller endpoints.
  • kit.spawnCluster(n, builderFn) — n coordinated instances for distributed-invariant tests.
• TestContainer — low-level DI container that accepts mocks in place of concrete services.
• createTestApp — compiles an app without opening real sockets; use .get / .post / etc.
• mockService / spyOn / mockFn / mockResolves — thin wrappers over node:test mocks with DI-aware typings.
• InMemoryLockProvider — lock primitive without Postgres, useful for unit tests.

Docs

https://justscale.sh/docs/techniques/testing