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🧪JEST

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

  • Usage

    • With TypeScript

  • Custom matchers

    • toBeDisabled

    • toBeEnabled

    • toBeEmptyDOMElement

    • toBeInTheDocument

    • toBeInvalid

    • toBeRequired

    • toBeValid

    • toBeVisible

    • toContainElement

    • toContainHTML

    • toHaveAccessibleDescription

    • toHaveAccessibleName

    • toHaveAttribute

    • toHaveClass

    • toHaveFocus

    • toHaveFormValues

    • toHaveStyle

    • toHaveTextContent

    • toHaveValue

    • toHaveDisplayValue

    • toBeChecked

    • toBePartiallyChecked

    • toHaveErrorMessage

  • Deprecated matchers

    • toBeEmpty

    • toBeInTheDOM

    • toHaveDescription

  • Inspiration

  • Other Solutions

  • Guiding Principles

  • Contributors

  • LICENSE

Installation

This module is distributed via [npm][npm] which is bundled with [node][node] and should be installed as one of your project's devDependencies:

or

for installation with yarn package manager.

Note: We also recommend installing the jest-dom eslint plugin which provides auto-fixable lint rules that prevent false positive tests and improve test readability by ensuring you are using the right matchers in your tests. More details can be found at eslint-plugin-jest-dom.

Usage

Import @testing-library/jest-dom once (for instance in your tests setup file) and you're good to go:

With TypeScript

If you're using TypeScript, make sure your setup file is a .ts and not a .js to include the necessary types.

You will also need to include your setup file in your tsconfig.json if you haven't already:

Custom matchers

@testing-library/jest-dom can work with any library or framework that returns DOM elements from queries. The custom matcher examples below are written using matchers from @testing-library's suite of libraries (e.g. getByTestId, queryByTestId, getByText, etc.)

toBeDisabled

This allows you to check whether an element is disabled from the user's perspective. According to the specification, the following elements can be disabled: button, input, select, textarea, optgroup, option, fieldset, and custom elements.

This custom matcher considers an element as disabled if the element is among the types of elements that can be disabled (listed above), and the disabled attribute is present. It will also consider the element as disabled if it's inside a parent form element that supports being disabled and has the disabled attribute present.

Examples

This custom matcher does not take into account the presence or absence of the aria-disabled attribute. For more on why this is the case, check #144.

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.

This custom matcher does not take into account the presence or absence of the aria-disabled attribute. For more on why this is the case, check #144.

toBeEmptyDOMElement

This allows you to assert whether an element has no visible content for the user. It ignores comments but will fail if the element contains white-space.

Examples

toBeInTheDocument

This allows you to assert whether an element is present in the document or not.

Examples

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

This allows you to check if an element, is currently invalid.

An element is invalid if it has an aria-invalid attribute with no value or a value of "true", or if the result of checkValidity() is false.

Examples

toBeRequired

This allows you to check if a form element is currently required.

An element is required if it is having a required or aria-required="true" attribute.

Examples

toBeValid

This allows you to check if the value of an element, is currently valid.

An element is valid if it has no aria-invalid attributes or an attribute value of "false". The result of checkValidity() must also be true if it's a form element.

Examples

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 is present in the document

  • 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

  • if <details /> it has the open attribute

Examples

toContainElement

This allows you to assert whether an element contains another element as a descendant or not.

Examples

toContainHTML

Assert whether a string representing a HTML element is contained in another element. The string should contain valid html, and not any incomplete html.

Examples

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.

toHaveAccessibleDescription

This allows you to assert that an element has the expected accessible description.

You can pass the exact string of the expected accessible description, or you can make a partial match passing a regular expression, or by using expect.stringContaining/expect.stringMatching.

Examples

toHaveAccessibleName

This allows you to assert that an element has the expected accessible name. It is useful, for instance, to assert that form elements and buttons are properly labelled.

You can pass the exact string of the expected accessible name, or you can make a partial match passing a regular expression, or by using expect.stringContaining/expect.stringMatching.

Examples

toHaveAttribute

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

toHaveClass

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

toHaveFocus

This allows you to assert whether an element has focus or not.

Examples

toHaveFormValues

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

toHaveStyle

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

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

This allows you to check whether the given node has a text content or not. This supports elements, but also text nodes and fragments.

When a string argument is passed through, it will perform a partial case-sensitive match to the node 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

toHaveValue

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 <input type="checkbox"> and <input type="radio">, which can be meaningfully matched only using toBeChecked or toHaveFormValues.

For all other form elements, the value is matched using the same algorithm as in toHaveFormValues does.

Examples

Using DOM Testing Library

toHaveDisplayValue

This allows you to check whether the given form element has the specified displayed value (the one the end user will see). It accepts <input>, <select> and <textarea> elements with the exception of <input type="checkbox"> and <input type="radio">, which can be meaningfully matched only using toBeChecked or toHaveFormValues.

Examples

Using DOM Testing Library

toBeChecked

This allows you to check whether the given element is checked. It accepts an input of type checkbox or radio and elements with a role of checkbox, radio or switch with a valid aria-checked attribute of "true" or "false".

Examples

toBePartiallyChecked

This allows you to check whether the given element is partially checked. It accepts an input of type checkbox and elements with a role of checkbox with a aria-checked="mixed", or input of type checkbox with indeterminate set to true

Examples

toHaveErrorMessage

This allows you to check whether the given element has an ARIA error message or not.

Use the aria-errormessage attribute to reference another element that contains custom error message text. Multiple ids is NOT allowed. Authors MUST use aria-invalid in conjunction with aria-errormessage. Learn more from aria-errormessage spec.

Whitespace is normalized.

When a string argument is passed through, it will perform a whole case-sensitive match to the error message text.

To perform a case-insensitive match, you can use a RegExp with the /i modifier.

To perform a partial match, you can pass a RegExp or use expect.stringContaining("partial string").

Examples

Deprecated matchers

toBeEmpty

Note: This matcher is being deprecated due to a name clash with jest-extended. See more info in #216. In the future, please use only toBeEmptyDOMElement

This allows you to assert whether an element has content or not.

Examples

toBeInTheDOM

This custom matcher is deprecated. Prefer toBeInTheDocument instead.

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 what "the DOM" is. Therefore, it does not check whether 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:

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.

toHaveDescription

This custom matcher is deprecated. Prefer toHaveAccessibleDescription instead, which is more comprehensive in implementing the official spec.

This allows you to check whether the given element has a description or not.

An element gets its description via the aria-describedby attribute. Set this to the id of one or more other elements. These elements may be nested inside, be outside, or a sibling of the passed in element.

Whitespace is normalized. Using multiple ids will join the referenced elements’ text content separated by a space.

When a string argument is passed through, it will perform a whole case-sensitive match to the description text.

To perform a case-insensitive match, you can use a RegExp with the /i modifier.

To perform a partial match, you can pass a RegExp or use expect.stringContaining("partial string").

Examples

Inspiration

This whole library was extracted out of Kent C. Dodds' [DOM Testing Library][dom-testing-library], which was in turn extracted out of [React Testing Library][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][prs] and add it here!

If you would like to further test the accessibility and validity of the DOM consider jest-axe. It doesn't overlap with jest-dom but can complement it for more in-depth accessibility checking (eg: validating aria attributes or ensuring unique id attributes).

Guiding Principles

[The more your tests resemble the way your software is used, the more confidence they can give you.][guiding-principle]

This library follows the same guiding principles as its mother library [DOM Testing Library][dom-testing-library]. Go [check them out][guiding-principle] 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.

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