@automock/jest

Automock

Automock optimizes the unit testing process by providing a virtual, isolated environment and automated mock generation, enabling developers to create efficient test suites and enhance their overall testing experience.

↗️ Documentation    ↗️ API Reference

Core Features

🚀 Zero-Setup Mocking - Automatically generate mock objects, eliminate manual setup, reduce boilerplate code.

🔍 Type-Safe Mocks - Leverage TypeScript's power with mocks that retain the same type as real objects.

📄 Consistent Tests Structure - Test suites will follow a consistent syntax and structure, making them easier to read and maintain.

📈 Optimized Performance - By bypassing the actual DI container, unit tests run significantly faster.

🌐 Community & Support - Join a growing community of developers.

:package: Installation

To fully integrate Automock into your testing and dependency injection framework, you need to install two packages: @automock/jest, and the corresponding DI framework adapter.

1. Install Automock's Jest package:

$ npm i -D @automock/jest

1. And for your DI framework, install the appropriate Automock adapter (as a dev dependency):

DI Framework	Package Name
NestJS	@automock/adapters.nestjs
Inversify	@automock/adapters.inversify

For example:

$ npm i -D @automock/jest @automock/adapters.nestjs

No further configuration is required.

:computer: Quick Example

Take a look at the following example:

Consider the following UserService class:

export class Database {
  async getUsers(): Promise<User[]> { ... }
}

export class UserService {
  constructor(private database: Database) {}

  async getAllUsers(): Promise<User[]> {
    return this.database.getUsers();
  }
}

Let's create a unit test for this class:

import { TestBed } from '@automock/jest';
import { Database, UserService } from './user.service'; 

describe('User Service Unit Spec', () => {
  let userService: UserService;
  let database: jest.Mocked<Database>;

  beforeAll(() => {
    const { unit, unitRef } = TestBed.create(UserService).compile();
    userService = unit;
    database = unitRef.get(Database);
  });

  test('should return users from the database', async () => {
    const mockUsers: User[] = [{ id: 1, name: 'John' }, { id: 2, name: 'Jane' }];
    database.getUsers.mockResolvedValue(mockUsers);

    const users = await userService.getAllUsers();

    expect(database.getUsers).toHaveBeenCalled();
    expect(users).toEqual(mockUsers);
  });
});

With the use of the TestBed, an instance of the UserService class can be created with mock objects automatically generated for its dependencies. During the test, we have direct access to the automatically generated mock object for the Database dependency (database). By stubbing the getUsers() method of the database mock object, we can define its behavior and make sure it resolves with a specific set of mock users.

Automock improves upon the existing unit testing procedures of DI frameworks by creating a virtual DI container. There is an array of advantages to this change:

• Speed: By simulating the actual DI container in the testing environment, Automock speeds up execution times.

• Efficiency: Developers are therefore able to focus on writing the test logic instead of grappling with the complexities of test setup.

• Isolation: Each test runs independently with mock implementations automatically provided, creating a streamlined and interference-free testing environment.

↗️ For a full Step-by-Step example

:scroll: License

Distributed under the MIT License. See LICENSE for more information.