FormData is not defined in React Jest

Question

I am writing a unit testing code for the React project. I am trying to test one function

//function aa
export const login = (values) => async => (dispatch) => {
  let bodyFormData = new FormData();

  bodyFormData.append('username', values.login);
  bodyFormData.append('password', values.password);
  return await axios({
   method: 'post',
   url: url,
   data: bodyFormData
  }
}

//aa test
it("Login Action", async () => {
  afterEach(() => {
    store.clearActions();
  });
  const values = {
    login: "aaaaa",
    password: "bbbbb"
  };
  const expectedResult = { type: "LOGIN_PASS" };

  const result = await store.dispatch(login(values));
  expect(result).toEqual(expectedResult);
});

In the browser, this works ok. but when testing I get below error

ReferenceError: FormData is not defined

I tried to use this module but no luck... https://www.npmjs.com/package/form-data

I do not want to just test axios, I need to test full function.

Answer 1

You will need to mock FormData within your unit test, as the FormData web API is not available in the node.js/jsdom environment.

function FormDataMock() {
  this.append = jest.fn();
}

global.FormData = FormDataMock

If you wish to mock other methods within the FormData global:

const entries = jest.fn()
global.FormData = () => ({ entries })