Lost in testing Redux vs Sinon/React - reactjs

Question

Im completely lost on how to test the React components itself which include XHR calls. I have below items
LoginForm
Redux with action + reducer
Sinon (for spy/xhr stuff)
Chai
Below is some basic setup code. Please note that its not the full code but i guess you get the idea:
Form
class Form extends React.Component {
constructor() {
super();
this.state = {
username: null,
password: null
};
this.handleForm = this.handleForm.bind(this);
}
handleForm(e) {
e.preventDefault();
this.props.dispatch(authenticateUser(this.state.username, this.state.password));
}
render() {
<Form>
}
}
Action
export function authenticateUser(username, password) {
return function(dispatch, getState) {
dispatch({type: 'AUTHENTICATION_USER'});
fetch(getState().config.login_endpoint, {
method: 'POST',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json',
},
body: {
username: username,
password: password
}
}).then(function (data) {
if(data.status === 404) {
dispatch({type: 'AUTHENTICATION_USER_NOTFOUND', payload: data.statusText});
} else {
dispatch({type: 'AUTHENTICATION_USER_FULFILLED', payload: data.json()});
}
}).catch(function (error) {
dispatch({type: 'AUTHENTICATION_USER_REJECTED', payload: error.message});
});
};
}
Reducer
export default function (state = {
loading: false,
errorMessage: null,
passwordSent: false
}, action) {
switch (action.type) {
case 'AUTHENTICATION_USER':
return {...state, loading: true, errorMessage:null};
case 'AUTHENTICATION_USER_NOTFOUND':
case 'AUTHENTICATION_USER_REJECTED':
return {...state, loading: false, errorMessage: action.payload};
case 'AUTHENTICATION_USER_FULFILLED':
window.location = '/';
break;
}
return state;
}
To test all this i setup a few test cases:
describe('components/LoginForm', () => {
it('should push username and password in xhr call after form submit');
it('redirects in case of succesfull login to the configured endpoint');
it('should show an user error on a 404 response');
it('should show an user error on a 500 response');
});
Testing of all the internal component stuff is already finished but no idea how we can handle the XHR stuff and also the redux events. I checked this page as reference but i really dont get the idea and it is also focussed on Jest instead
http://redux.js.org/docs/recipes/WritingTests.html
Hope that someone could bump me into the correct direction on how to handle this.
Thanks