How to test React component with AJAX in componentWillMount - reactjs

Question

I have a React component where some data is fetched via HTTP during componentWillMount.
This is done pretty much like explained here using the Redux Thunk middleware.
The request is done with axios.
So initially a loading state is set and the data will be set as soon as the request returns.
class SomeComponent extends Component {
//...
componentWillMount() {
store.dispatch(fetchInitialData())
}
// ...
}
The action doing the fetch:
export function fetchInitialData() {
return dispatch => {
return axios.get('https://our.api')
.then(res => {
dispatch(handleSuccess(res.data));
})
.catch(error => dispatch(handleError(error)));
}
}
The test is written with Jest and Enzyme and axios is mocked with axios-mock-adapter.
import Enzyme, { mount } from 'enzyme'
import Adapter from 'enzyme-adapter-react-16'
import configureMockStore from 'redux-mock-store'
import axios from 'axios'
import MockAdapter from 'axios-mock-adapter'
import thunk from 'redux-thunk'
import response from 'testdata/api/response.json'
Enzyme.configure({
adapter: new Adapter()
});
function createMockStore() {
const mockStore = configureMockStore([thunk]);
return mockStore({});
}
describe('some component', () => {
it('should render ...', () => {
const mock = new MockAdapter(axios);
mock.onGet('/our.api').reply(200, response);
const store = createMockStore();
const enzymeWrapper = mount(<SomeComponent store={store}/>);
console.log('enzymeWrapper', enzymeWrapper.html());
});
});
The problem is that the html of enzymeWrapper always contains only the representation of the initial state. The initial HTML never changes according to the new state from the response.
When I add logging to the reducers and services I see that the mocked requests executes and the state is filled with the mocked response.
But the component does not re-render with the new state data.
I want to point out that this is only an issue in the test. In the actual app everything works fine.
To me it seems that I need to somehow wait for the state changes to get applied. But I don't know how.