How to apply Global Pipes during e2e tests - nestjs

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

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 2

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 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.