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How to set up tests based on frameworks other than Express

This guide explains how to use itdoc with web frameworks other than Express.

NestJS Example​

Although NestJS internally uses Express, due to its structure, you need to manually create and pass an Express-type app instance to describeAPI. The example below assumes you are using the popular Jest test runner. If you're using a different runner, follow the equivalent setup according to its documentation.

1. Create globalSetup​

Using Jest globalSetup, spin up a test-only Nest application once and reuse it across all tests.

test/global-setup.ts :

import { Test, TestingModule } from '@nestjs/testing';
import { INestApplication } from '@nestjs/common';
import { AppModule } from '../src/app.module';
import type { App } from 'supertest/types';

declare global {
  // Expose the supertest handle globally for itdoc
  // eslint-disable-next-line no-var
  var __APP__: App;
}

export default async function globalSetup(): Promise<void> {
  const moduleFixture: TestingModule = await Test.createTestingModule({
    imports: [AppModule],
  }).compile();

  const app: INestApplication = moduleFixture.createNestApplication();
  await app.init();

  global.__APP__ = app.getHttpServer() as App;
}

2. Register globalSetup in Jest config​

Add the following to jest-e2e.json (or your Jest config file):

{
  "globalSetup": "<rootDir>/test/global-setup.ts"
}

3. Use itdoc in Test Code​

Pass global.__APP__ to the app argument of itdoc.

import { describeAPI, field, HttpMethod, HttpStatus, itDoc } from 'itdoc';

describeAPI(
  HttpMethod.GET,
  '/',
  {
    summary: 'Hello World',
    description: 'Returns greeting message',
    tag: 'hello',
  },
  global.__APP__, // ← Handle exposed globally in globalSetup
  // ... (rest of your itdoc code)
);