How to unit test a method of react component?

I am trying to unit test my reactjs component:

import React from 'react';
import Modal from 'react-modal';
import store from '../../../store'
import lodash from 'lodash'

export class AddToOrder extends React.Component {
  constructor(props) {
    super(props);
    this.state = {checked: false}
    //debugger
  }
  checkBoxChecked() {
    return true
  }
  render() {
    console.log('testing=this.props.id',this.props.id )
    return (
      <div className="order">
        <label>
          <input
            id={this.props.parent}
            checked={this.checkBoxChecked()}
            onChange={this.addToOrder.bind(this, this.props)}
            type="checkbox"/>
          Add to order
        </label>
      </div>
    )
  }
}

export default AddToOrder;

Just to get started I am already struggling to assert the checkBoxChecked method:

import React from 'react-native';
import {shallow} from 'enzyme';
import {AddToOrder} from '../app/components/buttons/addtoorder/addtoorder';
import {expect} from 'chai';
import {mount} from 'enzyme';
import jsdom from 'jsdom';
const doc = jsdom.jsdom('<!doctype html><html><body></body></html>')
global.document = doc
global.window = doc.defaultView

let props;
beforeEach(() => {
  props = {
    cart: {
      items: [{
        id: 100,
        price: 2000,
        name:'Docs'
      }]
    }
  };
});

describe('AddToOrder component', () => {
  it('should be handling checkboxChecked', () => {
    const wrapper = shallow(<AddToOrder {...props.cart} />);
    expect(wrapper.checkBoxChecked()).equals(true); //error appears here
  });
});

```

How can I unit test a method on the component? This is the error I am getting:

TypeError: Cannot read property 'checked' of undefined

You are almost there. Just change your expect to this:

expect(wrapper.instance().checkBoxChecked()).equals(true);

You can go through this link to know more about testing component methods using enzyme

For those who find the accepted answer as not working, try using .dive() on your shallow wrapper before using .instance():

expect(wrapper.dive().instance().somePrivateMethod()).toEqual(true);

Reference: Testing component methods with enzyme

Extend of previous answer. If you have connected component (Redux) , try next code :

 const store=configureStore();
  const context = { store };
   const wrapper = shallow(
      <MyComponent,
      { context },
    );
   const inst = wrapper.dive().instance();
   inst.myCustomMethod('hello');

How to unit test a method of react component?

Related

Recent Posts