How to mock Axios service wrapper using JEST - reactjs

Question

I'm using JEST testing framework to write test cases for my React JS application. I'm using our internal axios wrapper to make service call. I would like to mock that wrapper service using JEST. Can someone help me on this ?
import Client from 'service-library/dist/client';
import urls from './urls';
import { NODE_ENV, API_VERSION } from '../screens/constants';
const versionHeader = 'X-API-VERSION';
class ViewServiceClass extends Client {
getFiltersList(params) {
const config = {
method: urls.View.getFilters.requestType,
url: urls.View.getFilters.path(),
params,
headers: { [versionHeader]: API_VERSION },
};
return this.client.request(config);
}
const options = { environment: NODE_ENV };
const ViewService = new ViewServiceClass(options);
export default ViewService;
Above is the Service Implementation to make API call. Which I'm leveraging that axios implementation from our internal library.
getFiltersData = () => {
const params = {
filters: 'x,y,z',
};
let {
abc,
def,
ghi
} = this.state;
trackPromise(
ViewService.getFiltersList(params)
.then((result) => {
if (result.status === 200 && result.data) {
const filtersJson = result.data;
.catch(() =>
this.setState({
alertMessage: 'No Filters Data Found. Please try after some time',
severity: 'error',
showAlert: true,
})
)
);
};
I'm using the ViewService to get the response, and I would like to mock this service. Can someone help me on this ?

Answer 1

You would need to spy your getFiltersList method from ViewServiceClass class.
Then mocking some response data (a Promise), something like:
import ViewService from '..';
const mockedData = {
status: 'ok',
data: ['some-data']
};
const mockedFn = jest.fn(() => Promise.resolve(mockedData));
let getFiltersListSpy;
// spy the method and set the mocked data before all tests execution
beforeAll(() => {
getFiltersListSpy = jest.spyOn(ViewService, 'getFiltersList');
getFiltersListSpy.mockReturnValue(mockedFn);
});
// clear the mock the method after all tests execution
afterAll(() => {
getFiltersListSpy.mockClear();
});
// call your method, should be returning same content as `mockedData` const
test('init', async () => {
const response = await ViewService.getFiltersList();
expect(response).toEqual(mockedData);
});
P.D: You can pass params to the method, but you will need to configure as well the mockedData as you wish.