I am trying to perform some unit testing on my existing react application with Jest and Enzyme. I am totally new to this stuff and accurately I do not know how to approach such test scenarios. I know that to test API request calls I have to perform some "mocking", but how should I write the test for that?. What will be the steps that needs to be followed?

Following is the code snippet I am looking to test.

Home.js

```
import React,{Component} from 'react'
import axios from 'axios';
import {Link} from 'react-router-dom';
import FacilityModal from '../Table/FacilityModal';

class Home extends Component {
  state = {
    cities:[],
    name:''
  }

  componentDidMount() {
    axios.get('/cities').then(res => {
      this.setState({cities:res.data})
      console.log("Oza" + JSON.stringify(res))
    });
    console.log(this.state.cities)
  }

  render() {
    let postList = this.state.cities.map(city => {
      return(
        <div key = {city.id}>
          <p>
            <Link to = {'/'+city.id}>{city.name}</Link>
          </p>
        </div>
      )
    })
    return(
      <div className = 'align'>All Facilities (NCAL)
        <div className="hr-sect">OR</div>
        <div className = 'Modal'>
          {postList}
        </div>
        <FacilityModal cityname = {this.props} />
      </div>
    )
  }
}

```