How to cover ajax calls in jest code coverage

Question

I have following method in vue file in which api call is there as below

getZipcode(city){
         ajax.get(`${CONSTANTS.STANDARDAPIURL}Geographic/ZipCode?cityName=${city}`, {}, (res) => {
                this.zipCode = res.data.zipCode
          })
    }

and i have defined this ajax in ajax.js file

window.ajax = {
get(url, params, successCallback, errorCallback,coordinates) {
    var that = this;
    let latitude = coordinates == undefined ? "" : coordinates.latitude
    let longitude = coordinates == undefined ? "" : coordinates.longitude
    axios({
      method: "get",
      url: that.formatURL(url),
      params: params,
      responseType: "json",
      headers: { 'X-USER-COORDINATES': `${latitude},${longitude}`}
    })
    .then(function(response) {
        if (
          response.data.Message != null &&
          response.data.Message != "" &&
          response.data.Message ==
            "Authorization has been denied for this request."
        ) {
          window.location.href = "/account/login";
        } else {
          successCallback(response);
        }
      })
      .catch(function(error) {
        that.catchException(error, errorCallback);
      });
} }

I have written test case as

test("getZipcode method", () => {
    window.ajax = {
        get: jest.fn()
    }
    var wrapper = mount(EmployeeInfo)
    wrapper.vm.getZipcode('city')
    expect(window.ajax.get).toHaveBeenCalled()
})

The test has been passed but the ajax call lines were not covered in code coverage as u can see in the image method coverage

Is there any way to write the test case to cover the ajax api calls

Thanks

Answer 1

I resolved the above problem with following test case

test(`getZipcode method`, () => {
    var res = { data: { zipCode: '72015' } }
    const mockAjax = sinon.stub(window.ajax, 'get').callsArgWith(2, res)
    wrapper.vm.getZipcode('city')
    sinon.assert.calledWith(window.ajax.get, `${CONSTANTS.STANDARDAPIURL}Geographic/ZipCode?cityName=city`)
    mockAjax.restore()
})

Also installed babel-plugin-istanbul package and now the method covers as expected method coverage

Thanks