Ajuda com testes no react ComponentDidMount, axios e setState

index.js

import React from 'react';
import { connect } from 'react-redux';
import {
  Container, Grid, Menu,
} from 'semantic-ui-react';

import CustomerService from '../../services/CustomerService';
import { customerListStart, customerListSuccess, customerListError } from './actions';
import Create from './Create';
import List from './List';

export class Customers extends React.Component {
  state = { customers: [] };

  componentDidMount() {
    this.fetch();
  }

  fetch = () => {
    const { handleStart, handleSuccess, handleError } = this.props;
    handleStart();
    CustomerService.list()
      .then((response) => {
        const { data } = response.data;
        this.setState({ customers: data });
        handleSuccess();
      })
      .catch(error => handleError(error));
  }

  render() {
    const { customers } = this.state;

    return (
      <div style={{ marginTop: '7em' }}>
        <Container>
          <Grid>
            <Grid.Row>
              <Grid.Column>
                <Menu secondary>
                  <Menu.Menu position="right">
                    <Menu.Item><Create handleFetch={this.fetch} /></Menu.Item>
                  </Menu.Menu>
                </Menu>
              </Grid.Column>
            </Grid.Row>
            <List customers={customers} />
          </Grid>
        </Container>
      </div>
    );
  }
}
const mapStateToProps = () => ({});

const mapDispatchToProps = dispatch => ({
  handleStart() { dispatch(customerListStart()); },
  handleSuccess() { dispatch(customerListSuccess()); },
  handleError(payload) { dispatch(customerListError(payload)); },
});

const ConnectCustomers = connect(mapStateToProps, mapDispatchToProps)(Customers);

export default ConnectCustomers;

index.test.js

import React from 'react';
import axios from 'axios';
import { shallow } from 'enzyme';

import { CustomerResponse } from '../../../factories/customers';
import { Customers } from '../index';

jest.mock('axios');

// jest.mock('../../../services/CustomerService', () => {
//   return { list: jest.fn() };
// });

const getWrapper = () => {
  const props = {
    handleStart: jest.fn().mockName('handleStart'),
    handleSuccess: jest.fn().mockName('handleSuccess'),
    handleError: jest.fn().mockName('handleError'),
  };

  const wrapper = shallow(<Customers {...props} />);
  return { wrapper };
};

describe('Customers component', () => {
  beforeEach(() => {
    axios.get.mockClear();
  });
  it('should render Customers', async (done) => {
    const response = CustomerResponse.build();
    const headers = { headers: { Authorization: 'Bearer undefined' } };
    axios.get.mockResolvedValue(response);
    console.log(response)
    const { wrapper } = getWrapper();
    const instance = wrapper.instance();
    instance.componentDidMount();
    console.log(instance.state)

    expect(axios.get).toHaveBeenCalled();
    expect(axios.get).toHaveBeenCalledWith('/customers', headers);
    expect(wrapper.setState).toHaveBeenCalled()
    expect(wrapper.state('customers')).toBe([]);
    wrapper.update()
    expect(wrapper).toMatchSnapshot();
    done();

  });
});

jestlogger.txt

Customers component
    ✕ should render Customers (8ms)

  ● Customers component › should render Customers

    expect(jest.fn())[.not].toHaveBeenCalled()

    Matcher error: received value must be a mock or spy function

    Received has type:  function
    Received has value: [Function setState]

      39 |     expect(axios.get).toHaveBeenCalled();
      40 |     expect(axios.get).toHaveBeenCalledWith('/customers', headers);
    > 41 |     expect(wrapper.setState).toHaveBeenCalled()
         |                              ^
      42 |     expect(wrapper.state('customers')).toBe([]);
      43 |     wrapper.update()
      44 |     expect(wrapper).toMatchSnapshot();

      at Object.toHaveBeenCalled (src/containers/Customers/__tests__/index.test.js:41:30)

  console.log src/containers/Customers/__tests__/index.test.js:33
    { data:
       [ { id: '1',
           name: 'Customer 1',
           email: 'customer-1@mail.com',
           cnpj: '137894561231',
           phone: '31 99125 6051',
           contact: 'Jhon Doe 1',
           amount: 72000 },
         { id: '2',
           name: 'Customer 2',
           email: 'customer-2@mail.com',
           cnpj: '137894561232',
           phone: '31 99125 6052',
           contact: 'Jhon Doe 2',
           amount: 72000 },
         { id: '3',
           name: 'Customer 3',
           email: 'customer-3@mail.com',
           cnpj: '137894561233',
           phone: '31 99125 6053',
           contact: 'Jhon Doe 3',
           amount: 72000 },
         { id: '4',
           name: 'Customer 4',
           email: 'customer-4@mail.com',
           cnpj: '137894561234',
           phone: '31 99125 6054',
           contact: 'Jhon Doe 4',
           amount: 72000 } ],
      message: 'Lista os/as Customers paginados(as).',
      page: 1,
      pages: 1,
      params: { page_size: 10 },
      resource: 'Customers',
      status: 200,
      total: 3 }

  console.log src/services/CustomerService.js:14
    { Authorization: 'Bearer undefined' }

  console.log src/services/CustomerService.js:14
    { Authorization: 'Bearer undefined' }

  console.log src/containers/Customers/__tests__/index.test.js:37
    { customers: [] }

Test Suites: 1 failed, 1 total
Tests:       1 failed, 1 total
Snapshots:   0 total
Time:        1.002s
Ran all test suites matching /src\/containers\/Customers\/__tests__\/index.test.js/i