How to apply Global Pipes during e2e tests

Question

How do you apply global pipes when using Test.createTestingModule?

Normally, global pipes are added when the application is mounted in main.ts.

beforeEach(async done => {
    const moduleFixture: TestingModule = await Test.createTestingModule({
      imports: [AppModule]
    }).compile()

    app = moduleFixture.createNestApplication()
    await app.init()
    done()
  })

Answer 1

You can add them before you initialize the testing module:

  beforeEach(async done => {
    const moduleFixture: TestingModule = await Test.createTestingModule({
      imports: [AppModule]
    }).compile()

    app = moduleFixture.createNestApplication()

    // Add global pipe here
    app.useGlobalPipes(new ValidationPipe({ transform: true, whitelist: true, forbidNonWhitelisted: true }))

    await app.init()
    done()
  })

Answer 2

Here's what I do to ensure that the global pipes in my main.ts file are always in sync with my testing setup...

Start by creating a new file called main.config.ts, this should contain your global pipes, filters, etc:

import { INestApplication, ValidationPipe } from "@nestjs/common";

export function mainConfig(app: INestApplication) {
  app.enableCors();
  app.useGlobalPipes(new ValidationPipe());
}

Next, use the newly created mainConfig function in both the main.ts and app.e2e-spec.ts (or wherever you setup your tests):

main.ts

import { NestFactory } from "@nestjs/core";
import { mainConfig } from "main.config";
import { AppModule } from "./app.module";

async function bootstrap() {
  const app = await NestFactory.create(AppModule);

  // use here
  mainConfig(app);

  await app.listen(3000);
}

bootstrap();

app.e2e-spec.ts

import { INestApplication } from "@nestjs/common";
import { TestingModule, Test } from "@nestjs/testing";
import { AppModule } from "app.module";
import { mainConfig } from "main.config";

let app: INestApplication;

beforeEach(async () => {
  const moduleFixture: TestingModule = await Test.createTestingModule({
    imports: [AppModule],
  }).compile();

  app = moduleFixture.createNestApplication();

  // use here
  mainConfig(app);

  await app.init();
});

Now if you need to add a new pipe, you'll only have to make the change in one spot (main.config.ts) to see it reflected in both the app and the tests.

Answer 3

Another approach is to declare the global pipes in the module using APP_PIPE.

@Module({
  providers: [
    {
      provide: APP_PIPE,
      useClass: ValidationPipe,
    },
  ],
})
export class AppModule {}

Then it will be available in your e2e tests.