helpers.spec.js

import MyService from './api';

const service = new MyService();

describe('MY API Service', () => {
  let data;
  beforeEach(async () => {
    const currentUser = {
      firstName: 'My',
      lastName: 'Name',
      gender: 'male',
      dateOfBirth: null,
      //... rest of data
    };
    data = await service.login(
      currentUser.firstName,
      currentUser.lastName,
      currentUser.dateOfBirth,
      //...rest of data
    );
  });
  it('have a correct login functionality', async () => {
    const blob = await data.json();
    expect(data.status).toEqual(200);
    expect(blob.message).toEqual('success');
  });
});