jest-dom
Custom jest matchers to test the state of the DOM
The problem
You want to use jest to write tests that assert various things about the
state of a DOM. As part of that goal, you want to avoid all the repetitive
patterns that arise in doing so. Checking for an element's attributes, its text
content, its css classes, you name it.
This solution
The @testing-library/jest-dom
library provides a set of custom jest matchers
that you can use to extend jest. These will make your tests more declarative,
clear to read and to maintain.
Table of Contents
Installation
This module is distributed via npm which is bundled with node and
should be installed as one of your project's devDependencies
:
npm install --save-dev @testing-library/jest-dom
Usage
Import @testing-library/jest-dom/extend-expect
once (for instance in your
tests setup file) and you're good to go:
import '@testing-library/jest-dom/extend-expect'
Alternatively, you can selectively import only the matchers you intend to use,
and extend jest's expect
yourself:
import {toBeInTheDocument, toHaveClass} from '@testing-library/jest-dom'
expect.extend({toBeInTheDocument, toHaveClass})
Note: when using TypeScript, this way of importing matchers won't provide the
necessary type definitions. More on this
here.
Custom matchers
@testing-library/jest-dom
can work with any library or framework that returns
DOM elements from queries. The custom matcher examples below demonstrate using
document.querySelector
and
dom-testing-library for
querying DOM elements.
toBeDisabled
toBeDisabled()
This allows you to check whether an element is disabled from the user's
perspective.
It matches if the element is a form control and the disabled
attribute is
specified on this element or the element is a descendant of a form element with
a disabled
attribute.
According to the specification, the following elements can be
actually disabled:
button
, input
, select
, textarea
, optgroup
, option
, fieldset
.
Examples
<button data-testid="button" type="submit" disabled>submit</button>
<fieldset disabled><input type="text" data-testid="input" /></fieldset>
<a href="..." disabled>link</a>
Using document.querySelector
expect(document.querySelector('[data-testid="button"]')).toBeDisabled()
expect(document.querySelector('[data-testid="input"]')).toBeDisabled()
expect(document.querySelector('a')).not.toBeDisabled()
Using dom-testing-library
expect(getByTestId(container, 'button')).toBeDisabled()
expect(getByTestId(container, 'input')).toBeDisabled()
expect(getByText(container, 'link')).not.toBeDisabled()
toBeEnabled
toBeEnabled()
This allows you to check whether an element is not disabled from the user's
perspective.
It works like not.toBeDisabled()
. Use this matcher to avoid double negation in
your tests.
toBeEmpty
toBeEmpty()
This allows you to assert whether an element has content or not.
Examples
<span data-testid="not-empty"><span data-testid="empty"></span></span>
Using document.querySelector
expect(document.querySelector('[data-testid="empty"]').toBeEmpty()
expect(document.querySelector('[data-testid="not-empty"]').not.toBeEmpty()
Using dom-testing-library
expect(queryByTestId(container, 'empty')).toBeEmpty()
expect(queryByTestId(container, 'not-empty')).not.toBeEmpty()
toBeInTheDocument
toBeInTheDocument()
This allows you to assert whether an element is present in the document or not.
Examples
<span data-testid="html-element"><span>Html Element</span></span>
<svg data-testid="svg-element"></svg>
Using document.querySelector
const htmlElement = document.querySelector('[data-testid="html-element"]')
const svgElement = document.querySelector('[data-testid="svg-element"]')
const nonExistantElement = document.querySelector('does-not-exist')
const detachedElement = document.createElement('div')
expect(htmlElement).toBeInTheDocument()
expect(svgElement).toBeInTheDocument()
expect(nonExistantElement).not.toBeInTheDocument()
expect(detachedElement).not.toBeInTheDocument()
Using dom-testing-library
expect(
queryByTestId(document.documentElement, 'html-element'),
).toBeInTheDocument()
expect(
queryByTestId(document.documentElement, 'svg-element'),
).toBeInTheDocument()
expect(
queryByTestId(document.documentElement, 'does-not-exist'),
).not.toBeInTheDocument()
Note: This matcher does not find detached elements. The element must be added
to the document to be found by toBeInTheDocument. If you desire to search in a
detached element please use: toContainElement
toBeInvalid
toBeInvalid()
This allows you to check if an form element is currently invalid.
An element is invalid if it is having an
aria-invalid
attribute
or if the result of
checkValidity()
are false.
Examples
<input data-testid="no-aria-invalid" />
<input data-testid="aria-invalid" aria-invalid />
<input data-testid="aria-invalid-value" aria-invalid="true" />
<input data-testid="aria-invalid-false" aria-invalid="false" />
Using document.querySelector
expect(queryByTestId('no-aria-invalid')).not.toBeInvalid()
expect(queryByTestId('aria-invalid')).toBeInvalid()
expect(queryByTestId('aria-invalid-value')).toBeInvalid()
expect(queryByTestId('aria-invalid-false')).not.toBeInvalid()
Using dom-testing-library
expect(getByTestId(container, 'no-aria-invalid')).not.toBeInvalid()
expect(getByTestId(container, 'aria-invalid')).toBeInvalid()
expect(getByTestId(container, 'aria-invalid-value')).toBeInvalid()
expect(getByTestId(container, 'aria-invalid-false')).not.toBeInvalid()
toBeRequired
toBeRequired()
This allows you to check if an form element is currently required.
An element is required if it is having a required
or aria-required="true"
attribute.
Examples
<input data-testid="required-input" required />
<input data-testid="aria-required-input" aria-required="true" />
<input data-testid="conflicted-input" required aria-required="false" />
<input data-testid="aria-not-required-input" aria-required="false" />
<input data-testid="optional-input" />
<input data-testid="unsupported-type" type="image" required />
<select data-testid="select" required></select>
<textarea data-testid="textarea" required></textarea>
<div data-testid="supported-role" role="tree" required></div>
<div data-testid="supported-role-aria" role="tree" aria-required="true"></div>
Using document.querySelector
expect(document.querySelector('[data-testid="required-input"]')).toBeRequired()
expect(
document.querySelector('[data-testid="aria-required-input"]'),
).toBeRequired()
expect(
document.querySelector('[data-testid="conflicted-input"]'),
).toBeRequired()
expect(
document.querySelector('[data-testid="aria-not-required-input"]'),
).not.toBeRequired()
expect(
document.querySelector('[data-testid="unsupported-type"]'),
).not.toBeRequired()
expect(document.querySelector('[data-testid="select"]')).toBeRequired()
expect(document.querySelector('[data-testid="textarea"]')).toBeRequired()
expect(
document.querySelector('[data-testid="supported-role"]'),
).not.toBeRequired()
expect(
document.querySelector('[data-testid="supported-role-aria"]'),
).toBeRequired()
Using dom-testing-library
expect(getByTestId(container, 'required-input')).toBeRequired()
expect(getByTestId(container, 'aria-required-input')).toBeRequired()
expect(getByTestId(container, 'conflicted-input')).toBeRequired()
expect(getByTestId(container, 'aria-not-required-input')).not.toBeRequired()
expect(getByTestId(container, 'optional-input')).not.toBeRequired()
expect(getByTestId(container, 'unsupported-type')).not.toBeRequired()
expect(getByTestId(container, 'select')).toBeRequired()
expect(getByTestId(container, 'textarea')).toBeRequired()
expect(getByTestId(container, 'supported-role')).not.toBeRequired()
expect(getByTestId(container, 'supported-role-aria')).toBeRequired()
toBeValid
toBeValid()
This allows you to check if the value of a form element is currently valid.
An element is valid if it is not having an
aria-invalid
attribute
or having false
as a value and returning true
when calling
checkValidity()
.
Examples
<input data-testid="no-aria-invalid" />
<input data-testid="aria-invalid" aria-invalid />
<input data-testid="aria-invalid-value" aria-invalid="true" />
<input data-testid="aria-invalid-false" aria-invalid="false" />
Using document.querySelector
expect(queryByTestId('no-aria-invalid')).toBeValid()
expect(queryByTestId('aria-invalid')).not.toBeValid()
expect(queryByTestId('aria-invalid-value')).not.toBeValid()
expect(queryByTestId('aria-invalid-false')).toBeValid()
Using dom-testing-library
expect(getByTestId(container, 'no-aria-invalid')).toBeValid()
expect(getByTestId(container, 'aria-invalid')).not.toBeValid()
expect(getByTestId(container, 'aria-invalid-value')).not.toBeValid()
expect(getByTestId(container, 'aria-invalid-false')).toBeValid()
toBeVisible
toBeVisible()
This allows you to check if an element is currently visible to the user.
An element is visible if all the following conditions are met:
- it does not have its css property
display
set to none
- it does not have its css property
visibility
set to either hidden
or
collapse
- it does not have its css property
opacity
set to 0
- its parent element is also visible (and so on up to the top of the DOM tree)
- it does not have the
hidden
attribute
Examples
<div data-testid="zero-opacity" style="opacity: 0">Zero Opacity Example</div>
<div data-testid="visibility-hidden" style="visibility: hidden">
Visibility Hidden Example
</div>
<div data-testid="display-none" style="display: none">Display None Example</div>
<div style="opacity: 0">
<span data-testid="hidden-parent">Hidden Parent Example</span>
</div>
<div data-testid="visible">Visible Example</div>
<div data-testid="hidden-attribute" hidden>Hidden Attribute Example</div>
Using document.querySelector
expect(document.querySelector('[data-testid="zero-opacity"]')).not.toBeVisible()
expect(
document.querySelector('[data-testid="visibility-hidden"]'),
).not.toBeVisible()
expect(document.querySelector('[data-testid="display-none"]')).not.toBeVisible()
expect(
document.querySelector('[data-testid="hidden-parent"]'),
).not.toBeVisible()
expect(document.querySelector('[data-testid="visible"]')).toBeVisible()
expect(
document.querySelector('[data-testid="hidden-attribute"]'),
).not.toBeVisible()
Using dom-testing-library
expect(getByText(container, 'Zero Opacity Example')).not.toBeVisible()
expect(getByText(container, 'Visibility Hidden Example')).not.toBeVisible()
expect(getByText(container, 'Display None Example')).not.toBeVisible()
expect(getByText(container, 'Hidden Parent Example')).not.toBeVisible()
expect(getByText(container, 'Visible Example')).toBeVisible()
expect(getByText(container, 'Hidden Attribute Example')).not.toBeVisible()
toContainElement
toContainElement(element: HTMLElement | SVGElement | null)
This allows you to assert whether an element contains another element as a
descendant or not.
Examples
<span data-testid="ancestor"><span data-testid="descendant"></span></span>
Using document.querySelector
const ancestor = document.querySelector('[data-testid="ancestor"]')
const descendant = document.querySelector('[data-testid="descendant"]')
const nonExistantElement = document.querySelector(
'[data-testid="does-not-exist"]',
)
expect(ancestor).toContainElement(descendant)
expect(descendant).not.toContainElement(ancestor)
expect(ancestor).not.toContainElement(nonExistantElement)
Using dom-testing-library
const {queryByTestId} = render()
const ancestor = queryByTestId(container, 'ancestor')
const descendant = queryByTestId(container, 'descendant')
const nonExistantElement = queryByTestId(container, 'does-not-exist')
expect(ancestor).toContainElement(descendant)
expect(descendant).not.toContainElement(ancestor)
expect(ancestor).not.toContainElement(nonExistantElement)
toContainHTML
toContainHTML(htmlText: string)
Assert whether a string representing a HTML element is contained in another
element:
Examples
<span data-testid="parent"><span data-testid="child"></span></span>
Using document.querySelector
expect(document.querySelector('[data-testid="parent"]')).toContainHTML(
'<span data-testid="child"></span>',
)
Using dom-testing-library
expect(getByTestId(container, 'parent')).toContainHTML(
'<span data-testid="child"></span>',
)
Chances are you probably do not need to use this matcher. We encourage testing
from the perspective of how the user perceives the app in a browser. That's
why testing against a specific DOM structure is not advised.
It could be useful in situations where the code being tested renders html that
was obtained from an external source, and you want to validate that that html
code was used as intended.
It should not be used to check DOM structure that you control. Please use
toContainElement
instead.
toHaveAttribute
toHaveAttribute(attr: string, value?: any)
This allows you to check whether the given element has an attribute or not. You
can also optionally check that the attribute has a specific expected value or
partial match using
expect.stringContaining/expect.stringMatching
Examples
<button data-testid="ok-button" type="submit" disabled>ok</button>
Using document.querySelector
const button = document.querySelector('[data-testid="ok-button"]')
expect(button).toHaveAttribute('disabled')
expect(button).toHaveAttribute('type', 'submit')
expect(button).not.toHaveAttribute('type', 'button')
Using dom-testing-library
const button = getByTestId(container, 'ok-button')
expect(button).toHaveAttribute('disabled')
expect(button).toHaveAttribute('type', 'submit')
expect(button).not.toHaveAttribute('type', 'button')
expect(button).toHaveAttribute('type', expect.stringContaining('sub'))
expect(button).toHaveAttribute('type', expect.not.stringContaining('but'))
toHaveClass
toHaveClass(...classNames: string[])
This allows you to check whether the given element has certain classes within
its class
attribute.
You must provide at least one class, unless you are asserting that an element
does not have any classes.
Examples
<button data-testid="delete-button" class="btn extra btn-danger">
Delete item
</button>
<button data-testid="no-classes">No Classes</button>
Using document.querySelector
const deleteButton = document.querySelector('[data-testid="delete-button"]')
const noClasses = document.querySelector('[data-testid="no-classes"]')
expect(deleteButton).toHaveClass('extra')
expect(deleteButton).toHaveClass('btn-danger btn')
expect(deleteButton).toHaveClass('btn-danger', 'btn')
expect(deleteButton).not.toHaveClass('btn-link')
expect(noClasses).not.toHaveClass()
Using dom-testing-library
const deleteButton = getByTestId(container, 'delete-button')
const noClasses = getByTestId(container, 'no-classes')
expect(deleteButton).toHaveClass('extra')
expect(deleteButton).toHaveClass('btn-danger btn')
expect(deleteButton).toHaveClass('btn-danger', 'btn')
expect(deleteButton).not.toHaveClass('btn-link')
expect(noClasses).not.toHaveClass()
toHaveFocus
toHaveFocus()
This allows you to assert whether an element has focus or not.
Examples
<div><input type="text" data-testid="element-to-focus" /></div>
Using document.querySelector
const input = document.querySelector(['data-testid="element-to-focus"'])
input.focus()
expect(input).toHaveFocus()
input.blur()
expect(input).not.toHaveFocus()
Using dom-testing-library
const input = queryByTestId(container, 'element-to-focus')
fireEvent.focus(input)
expect(input).toHaveFocus()
fireEvent.blur(input)
expect(input).not.toHaveFocus()
toHaveFormValues
toHaveFormValues(expectedValues: {
[name: string]: any
})
This allows you to check if a form or fieldset contains form controls for each
given name, and having the specified value.
It is important to stress that this matcher can only be invoked on a form
or a fieldset element.
This allows it to take advantage of the .elements property in form
and
fieldset
to reliably fetch all form controls within them.
This also avoids the possibility that users provide a container that contains
more than one form
, thereby intermixing form controls that are not related,
and could even conflict with one another.
This matcher abstracts away the particularities with which a form control value
is obtained depending on the type of form control. For instance, <input>
elements have a value
attribute, but <select>
elements do not. Here's a list
of all cases covered:
<input type="number">
elements return the value as a number, instead of
a string.<input type="checkbox">
elements:
- if there's a single one with the given
name
attribute, it is treated as a
boolean, returning true
if the checkbox is checked, false
if
unchecked. - if there's more than one checkbox with the same
name
attribute, they are
all treated collectively as a single form control, which returns the value
as an array containing all the values of the selected checkboxes in the
collection.
<input type="radio">
elements are all grouped by the name
attribute, and
such a group treated as a single form control. This form control returns the
value as a string corresponding to the value
attribute of the selected
radio button within the group.<input type="text">
elements return the value as a string. This also
applies to <input>
elements having any other possible type
attribute
that's not explicitly covered in different rules above (e.g. search
,
email
, date
, password
, hidden
, etc.)<select>
elements without the multiple
attribute return the value as a
string corresponding to the value
attribute of the selected option
, or
undefined
if there's no selected option.<select multiple>
elements return the value as an array containing all
the values of the selected options.<textarea>
elements return their value as a string. The value
corresponds to their node content.
The above rules make it easy, for instance, to switch from using a single select
control to using a group of radio buttons. Or to switch from a multi select
control, to using a group of checkboxes. The resulting set of form values used
by this matcher to compare against would be the same.
Examples
<form data-testid="login-form">
<input type="text" name="username" value="jane.doe" />
<input type="password" name="password" value="12345678" />
<input type="checkbox" name="rememberMe" checked />
<button type="submit">Sign in</button>
</form>
const form = document.querySelector('[data-testid="login-form"]')
expect(form).toHaveFormValues({
username: 'jane.doe',
rememberMe: true,
})
toHaveStyle
toHaveStyle(css: string)
This allows you to check if a certain element has some specific css properties
with specific values applied. It matches only if the element has all the
expected properties applied, not just some of them.
Examples
<button data-testid="delete-button" style="display: none; color: red">
Delete item
</button>
Using document.querySelector
const button = document.querySelector(['data-testid="delete-button"'])
expect(button).toHaveStyle('display: none')
expect(button).toHaveStyle(`
color: red;
display: none;
`)
expect(button).not.toHaveStyle(`
color: blue;
display: none;
`)
Using dom-testing-library
const button = getByTestId(container, 'delete-button')
expect(button).toHaveStyle('display: none')
expect(button).toHaveStyle(`
color: red;
display: none;
`)
expect(button).not.toHaveStyle(`
color: blue;
display: none;
`)
This also works with rules that are applied to the element via a class name for
which some rules are defined in a stylesheet currently active in the document.
The usual rules of css precedence apply.
toHaveTextContent
toHaveTextContent(text: string | RegExp, options?: {normalizeWhitespace: boolean})
This allows you to check whether the given element has a text content or not.
When a string
argument is passed through, it will perform a partial
case-sensitive match to the element content.
To perform a case-insensitive match, you can use a RegExp
with the /i
modifier.
If you want to match the whole content, you can use a RegExp
to do it.
Examples
<span data-testid="text-content">Text Content</span>
Using document.querySelector
const element = document.querySelector('[data-testid="text-content"]')
expect(element).toHaveTextContent('Content')
expect(element).toHaveTextContent(/^Text Content$/)
expect(element).toHaveTextContent(/content$/i)
expect(element).not.toHaveTextContent('content')
Using dom-testing-library
const element = getByTestId(container, 'text-content')
expect(element).toHaveTextContent('Content')
expect(element).toHaveTextContent(/^Text Content$/)
expect(element).toHaveTextContent(/content$/i)
expect(element).not.toHaveTextContent('content')
toHaveValue
toHaveValue(value: string | string[] | number)
This allows you to check whether the given form element has the specified value.
It accepts <input>
, <select>
and <textarea>
elements with the exception of
of <input type="checkbox">
and <input type="radio">
, which can be
meaningfully matched only using toHaveFormValue
.
For all other form elements, the value is matched using the same algorithm as in
toHaveFormValue
does.
Examples
<input type="text" value="text" data-testid="input-text" />
<input type="number" value="5" data-testid="input-number" />
<input type="text" data-testid="input-empty" />
<select data-testid="multiple" multiple data-testid="select-number">
<option value="first">First Value</option>
<option value="second" selected>Second Value</option>
<option value="third" selected>Third Value</option>
</select>
Using document.querySelector
const textInput = document.querySelector('[data-testid="input-text"]')
const numberInput = document.querySelector('[data-testid="input-number"]')
const emptyInput = document.querySelector('[data-testid="input-empty"]')
const selectInput = document.querySelector('[data-testid="select-number"]')
expect(textInput).toHaveValue('text')
expect(numberInput).toHaveValue(5)
expect(emptyInput).not.toHaveValue()
expect(selectInput).not.toHaveValue(['second', 'third'])
Using dom-testing-library
const {getByTestId} = render()
const textInput = getByTestId('input-text')
const numberInput = getByTestId('input-number')
const emptyInput = getByTestId('input-empty')
const selectInput = getByTestId('select-number')
expect(textInput).toHaveValue('text')
expect(numberInput).toHaveValue(5)
expect(emptyInput).not.toHaveValue()
expect(selectInput).not.toHaveValue(['second', 'third'])
Deprecated matchers
toBeInTheDOM
toBeInTheDOM()
This allows you to check whether a value is a DOM element, or not.
Contrary to what its name implies, this matcher only checks that you passed to
it a valid DOM element. It does not have a clear definition of that "the DOM"
is. Therefore, it does not check wether that element is contained anywhere.
This is the main reason why this matcher is deprecated, and will be removed in
the next major release. You can follow the discussion around this decision in
more detail here.
As an alternative, you can use toBeInTheDocument
or
toContainElement
. Or if you just want to check if a value
is indeed an HTMLElement
you can always use some of
jest's built-in matchers:
expect(document.querySelector('.ok-button')).toBeInstanceOf(HTMLElement)
expect(document.querySelector('.cancel-button')).toBeTruthy()
Note: The differences between toBeInTheDOM
and toBeInTheDocument
are
significant. Replacing all uses of toBeInTheDOM
with toBeInTheDocument
will likely cause unintended consequences in your tests. Please make sure when
replacing toBeInTheDOM
to read through the documentation of the proposed
alternatives to see which use case works better for your needs.
Inspiration
This whole library was extracted out of Kent C. Dodds' dom-testing-library,
which was in turn extracted out of react-testing-library.
The intention is to make this available to be used independently of these other
libraries, and also to make it more clear that these other libraries are
independent from jest, and can be used with other tests runners as well.
Other Solutions
I'm not aware of any, if you are please make a pull request and add it
here!
Guiding Principles
The more your tests resemble the way your software is used, the more
confidence they can give you.
This library follows the same guiding principles as its mother library
dom-testing-library. Go
check them out
for more details.
Additionally, with respect to custom DOM matchers, this library aims to maintain
a minimal but useful set of them, while avoiding bloating itself with merely
convenient ones that can be easily achieved with other APIs. In general, the
overall criteria for what is considered a useful custom matcher to add to this
library, is that doing the equivalent assertion on our own makes the test code
more verbose, less clear in its intent, and/or harder to read.
Contributors
Thanks goes to these people (emoji key):
This project follows the all-contributors specification.
Contributions of any kind welcome!
LICENSE
MIT