MockClass

A tiny utility to quickly create Jasmine SpyObjs with all methods of a given class prototype spied. It reduces test setup boilerplate in JavaScript/TypeScript projects using Jasmine, regardless of the framework.

Installation

npm install mock-class

or

yarn add mock-class

Usage

Instead of manually creating mocks like following:

import { UserService } from './user.service';

const mockUserService = {
  addUser: jasmine.createSpy('addUser'),
  removeUser: jasmine.createSpy('removeUser'),
  getUsers: jasmine.createSpy('getUsers'),
  getUserDetails: jasmine.createSpy('getUserDetails'),
};

describe('UserComponent', () => {
  let component: UserComponent;
  let userService: UserService;

  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [
        { provide: UserService, useValue: mockUserService },
        // ... other providers
      ],
      // ... other config
    });

    component = TestBed.createComponent(UserComponent).componentInstance;
    userService = TestBed.inject(UserService);
  });

  it('should call getUsers', () => {
    component.someMethodThatUsesUserService();
    expect(userService.getUsers).toHaveBeenCalled();
  });
});

You can use mock-class to simplify tests:

import { mockClass } from 'mock-class';
import { UserService } from './user.service';

describe('UserComponent', () => {
  let component: UserComponent;
  let userService: UserService;

  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [
        { provide: UserService, useValue: mockClass(UserService) },
        // ... other providers
      ],
      // ... other config
    });

    component = TestBed.createComponent(UserComponent).componentInstance;
    userService = TestBed.inject(UserService);
  });

  it('should call getUsers', () => {
    component.someMethodThatUsesUserService();
    expect(userService.getUsers).toHaveBeenCalled();
  });
});

mockClass(UserService) automatically creates a Jasmine SpyObj where all methods of the UserService's prototype (including inherited methods) are spied. This removes the need to manually define each spy.

How it works

The mockClass function iterates through the prototype chain of the provided class, collecting all method names (excluding the constructor). It then uses jasmine.createSpyObj to create a spy object with spies for each of these methods.

TypeScript Support

mockClass is fully typed and provides type safety for your mocks. The return type of mockClass(MyService) will be jasmine.SpyObj<MyService>.

Contributing

Contributions are welcome! Please open an issue or submit a pull request on GitHub.

License

This project is licensed under the MIT License. See the LICENSE file for more details.