Test a function that calls an API

I need to test the fetchData() function. I have been trying to follow this (and many other) tutorials and trying to get it to work with my function for the past 3 hours but no luck so far. I'd preferably want to do it another way anyway because I don't think jQuery and React should be used together.

I essentially want to check if 1) the function is called when the search form has been submitted (button within SearchForm clicked) and 2) check if the data comes back.

Does anyone have any suggestions on how to get started please?

Thanks

Home

export default class Home extends Component {
  constructor() {
    super();
    this.state = {
      value: '',
      loading: false,
      dataError: false
    }
    this.nodes = [];
  }
  fetchData(e) {
    e.preventDefault();
    this.setState({loading: true});
    axios.get(`http://ift.tt/2lEbw7g}`)
    .then(res => {
      this.nodes = res.data.items.map((d, k) => <RepoItem {...d} key={k}/>);
      this.setState({loading: false});
    })
    .catch(err => {
      this.setState({dataError: true});
    });
  }
  render() {
    return (
      <div className="home-wrapper">
        <SearchForm value={this.state.value}
                    onSubmit={this.fetchData}
                    onChange={(e) => this.setState({value: e.target.value})}/>
        {this.state.loading ?
        <Spinner/>:
        !this.state.dataError ? this.nodes :
        <h1>Oops! Something went wrong, please try again!</h1>}
      </div>
    );
  }
}

RepoItem

export const RepoItem = props => (
  <div className="repo-item">
    <h1>{props.full_name}</h1>
  </div>);