My Controller function definition looks like that:
async login(@Req() request, @Body() loginDto: LoginDto): Promise<any> {
How I could prepare/mockup Request to provide first argument of function from Jest test?
Inside funciton I am setting headers using request.res.set. Should I somehow pass real Request object to function and then check if header is set or rather mockup whole Request object and check if set function was called?
I managed to do that mocking requests and response using node-mocks-http library.
const req = mocks.createRequest()
req.res = mocks.createResponse()
and then passing this as an argument.
const data = await authController.login(req, loginDto)
expect(req.res.get('AccessToken')).toBe(token.accessToken)
I followed a different approach and instead of using node-mocks-http library I used @golevelup/ts-jest, also, instead of testing if the function returns some value, like res.json() or res.status(), I checked if the function was called with the value I wanted to.
I borrowed this approach from Kent C. Dodds's testing workshop, take a look for similar ideas. Anyway, this is what I did in order to mock the Response dependency of my Controller's route:
// cars.controller.spec.ts
import { createMock } from '@golevelup/ts-jest';
const mockResponseObject = () => {
return createMock<Response>({
json: jest.fn().mockReturnThis(),
status: jest.fn().mockReturnThis(),
});
};
... ommited for brevity
it('should return an array of Cars', async () => {
const response = mockResponseObject();
jest
.spyOn(carsService, 'findAll')
.mockImplementation(jest.fn().mockResolvedValueOnce(mockedCarsList));
await carsController.getCars(response);
expect(response.json).toHaveBeenCalledTimes(1);
expect(response.json).toHaveBeenCalledWith({ cars: mockedCarsList });
expect(response.status).toHaveBeenCalledTimes(1);
expect(response.status).toHaveBeenCalledWith(200);
});
And that's it, I think that the implementation details aren't that important but in any case I'll leave the link to the Github repo where you can find the whole project.