ReactTestUtils - Simulate events - Click, Change, Mouse Over etc

This is the child article of ReactTestUtils - Tutorial. In this article, I will explain how to Simulate events - Click, Change, Key Up, Mouse Over etc.

Examples - Source Code

Example

Observe below example component. This component handles click, double click, mouse over, change events.

import React from 'react';

class EventComponent  extends React.Component {

    constructor(props) {
        super(props);
        this.state = {
            clickClass:'',
            dblClickClass:'',
            mouseOverEventClass:'',
            inputVal:''
        }
        this.clickEventFunc = this.clickEventFunc.bind(this);
        this.dblClickEventFunc = this.dblClickEventFunc.bind(this);
        this.onChange = this.onChange.bind(this);
        this.mouseOverEventFunc = this.mouseOverEventFunc.bind(this);
    }

    clickEventFunc() {
        this.setState({
            clickClass:'click-class'
        });
    }

    dblClickEventFunc() {
        this.setState({
            dblClickClass:'dblclick-class'
        });
    }

    mouseOverEventFunc() {
        this.setState({
            mouseOverEventClass:'mouseover-class'
        });
    }

    onChange(event) {
        this.setState({
            inputVal:event.target.value
        });
    }

    render () {
        return <div>
      <div id="clickEventDiv" className={this.state.clickClass} onClick={this.clickEventFunc}>
      </div>
      <div id="dblClickEventDiv" className={this.state.dblClickClass} onDoubleClick={this.dblClickEventFunc}>
      </div>
      <div id="mouseOverEventDiv" className={this.state.mouseOverEventClass} onMouseOver={this.mouseOverEventFunc}>
      </div>
            <input id="inputElm" value={this.state.inputVal} onChange={this.onChange}></input>
    </div>;
    }

}

EventComponent.propTypes = {

}

EventComponent.defaultProps = {

}

export default EventComponent;

Find Component by ID

This is small utility function which we use to find element by Id

function scryRenderedDOMComponentsWithId(tree, id) {
  return ReactTestUtils.findAllInRenderedTree(tree, function(inst) {
    return ReactTestUtils.isDOMComponent(inst) && inst.id === id;
  });
}

Click Event

When we click on the clickEventDiv component, click-class will be added. This test case verifies the class

it('click event test', () => {
    let instance = ReactTestUtils.renderIntoDocument(
      <EventComponent/>
    );
    let clickDiv = scryRenderedDOMComponentsWithId(instance, "clickEventDiv");
    ReactTestUtils.Simulate.click(clickDiv[0]);
    expect(clickDiv[0].className.match(/\bclick-class\b/)).toExist();
});

Double Click Event

When we double click on the dbClickEventDiv component, dblclick-class will be added. This test case verifies the class

  it('double click event test', () => {
    let instance = ReactTestUtils.renderIntoDocument(
      <EventComponent/>
    );
    let dbClickDiv = scryRenderedDOMComponentsWithId(instance, "dblClickEventDiv");
    ReactTestUtils.Simulate.doubleClick(dbClickDiv[0]);
    expect(dbClickDiv[0].className.match(/\bdblclick-class\b/)).toExist();
});

Mouse Over Event

When we double click on the mouseOverEventDiv component, mouseover-class will be added. This test case verifies the class

it('mouser over event test', () => {
    let instance = ReactTestUtils.renderIntoDocument(
      <EventComponent/>
    );
    let mOverDiv = scryRenderedDOMComponentsWithId(instance, "mouseOverEventDiv");
    ReactTestUtils.Simulate.mouseOver(mOverDiv[0]);
    expect(mOverDiv[0].className.match(/\bmouseover-class\b/)).toExist();
});

Change Event

When we change the input value of inputElm component, inputVal state variable changes. This test case verifies the state variable

it('change event test', () => {
    let instance = ReactTestUtils.renderIntoDocument(
      <EventComponent/>
    );
    let inputElm = scryRenderedDOMComponentsWithId(instance, "inputElm");
    inputElm[0].value = 'some value';
    ReactTestUtils.Simulate.change(inputElm[0]);
    expect(instance.state.inputVal).toEqual("some value");
});

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