Monday, 26 November 2018

Enzyme Cheat Sheet

Here is a reminder of the enzyme tips I've picked up so I don't forget!

Basics

Mount a react component in a test

import React from 'react'
import { mount } from 'enzyme'

describe('MyReactComponent', () => {
  const $ = mount(
     <MyReactComponent />
  )

  ...
})

Now different expectations and finds can be used to test,

A React Class
expect($.find('MyReactClass').exists()).toBe(false)

An html element
expect($.find('button').exists()).toBe(false)

An html id
expect($.find('#my-id').exists()).toBe(false)

A style
expect($.find('.some-style').exists()).toBe(false)

Html properties
expect($.find('[aria-label="Save"]').exists()).toBe(false)
expect($.find('[title="Save"]').exists()).toBe(false)

Combination - Html element & Property
expect($.find('button[title="Save"]').exists()).toBe(false)

HTML / Text / Contains

Text content.  Find the first of many 'myClass' css classes and check the text of the element
expect($.find('.myclass').text()).toContain("My Value")
expect($.find('.myclass
').text()).not.toContain("My Value")

As above but with an exact text match
expect($.find('.myclass
').text()).toBe("The exact text")
As above but getting the whole html of the element rather than just the text
expect($.find('.myclass').at(0).html()).toBe("<div>something</div>")

Focus

Focus a field with enzyme
const inputField = $.find('#myInput')
inputField.getDOMNode().focus()

Validate that a field has focus
expect(document.activeElement.id).toBe('the id expected')

Props

Find an element and get the html properties
const button = $.find('[aria-label="My Button"]')
expect(button.props().disabled).not.toBe(true)

Once an element has been found the react props can be used for expectations by also using props()
expect($.find('MyReactClass').props().options).toEqual([{option: 'option1'}, {option: 'option2'}])






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