开玩笑：模拟嵌套的 function 多次返回键/值对

Question

I am writing a test for an API which calls a nested api multiple times to get a key value pair. The value will always be a boolean and I am trying to mock this service aka KeyValueService in the code below. These and other more booleans are used in the PhotoService and I would like to mock these values so I can change the test to match these values.

I have mocked the booleans and also tried setting mockResolveValuetwice to true twice thinking that it may apply true for both variables valueA and valueB , but it did not work. I will be using this nested service multiple times and not just twice. So far none of the solutions worked. How can I get a desired value for each key value pair? TIA!

jest.mock('../../service/keyValue.service', () => ({
  valueA: false,
  valueB: false
}));

describe('PhotosService', () => {
  let service: PhotosService;
  let keyValueService: KeyValueService;
  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      providers: [PhotosService],
    }).compile();
    
    service = module.get<PhotosService>(PhotosService);
    keyValueService.get.mockResolveValue(() => true);
  });

  it('should be defined', () => {
    expect(service).toBeDefined();
    valueA.mockResolveValue(() => true);
  });
});

But the values doesnt change. I also tried the following,

  it('should be defined', () => {
    keyValueService.get.mockResolveValue(true);
    keyValueService.get.mockResolveValue(true);
    expect(service).toBeDefined();
    valueA.mockResolveValue(() => true);
  });

Answer 1

Alright one thing that worked for me was to set keyValueService.get again in my test or it block to jest.fn() again which worked for me to resolve this issue.

keyValueService.get = jest.fn()...;

Upto to use what you want. Either mockImplementation if need be or mockReturnValue etc. My guess is that it just reassigns the get function to a new mock value for that particular it/test block.