@joern.kalz/nest-test-setup

Convenient setup of testing modules for Nest applications.

Motivation

Setting up a testing module including mocks in a Nest applications usually requires some boilerplate code.

This package provides a concise way for defining a testing modules.

Installation

npm i -D @joern.kalz/nest-test-setup

or

yarn add -D @joern.kalz/nest-test-setup

In the jest section of your package.json change the entry testEnvironment to:

"testEnvironment": "../node_modules/@joern.kalz/nest-test-setup/env.js"

Usage

Unit Testing Controllers

With a controller depending on a service

// my.controller.ts

@Controller()
export class MyController {
  constructor(private readonly myService: MyService) {}
  @Get()
  getGreeting(): string {
    return this.myService.getGreetingText();
  }
}

// my.service.ts

@Injectable()
export class MyService {
  getGreetingText(): string {
    return "Hello!";
  }
}

You can test MyController with

import {
  controller,
  createTestingModule,
  mockProvider,
} from "@joern.kalz/nest-test-setup";

describe("setup", () => {
  const myController = controller(AppController);
  const myServiceMock = mockProvider(AppService);
  beforeEach(createTestingModule);

  it("should create test module", () => {
    myServiceMock.getGreeting.mockReturnValue("Hello world");
    expect(myController.getHello()).toBe("Hello world");
  });
});

Unit Testing Services

With a service depending on another service

// my.service.ts

@Injectable()
export class MyService {
  constructor(private readonly myOtherService: MyOtherService) {}
  getGreetingText(): string {
    return `Hello ${this.myOtherService.getName()}`;
  }
}

// my.other.service.ts

@Injectable()
export class MyOtherService {
  getName(): string {
    return "all";
  }
}

You can test MyService with

import {
  createTestingModule,
  mockProvider,
  provider,
} from "@joern.kalz/nest-test-setup";

describe("setup", () => {
  const myService = provider(MyService);
  const myOtherServiceMock = mockProvider(MyOtherService);
  beforeEach(createTestingModule);

  it("should create test module", () => {
    myOtherServiceMock.getName.mockReturnValue("world");
    expect(myService.getGreetingText()).toBe("Hello world");
  });
});

Contribute

Contributions welcome!