@iangrainger/jasmine-dom

Custom Jasmine matchers for testing DOM elements


Keywords
testing, dom, jasmine, matchers, jsdom
License
MIT
Install
npm install @iangrainger/jasmine-dom@0.0.1

Documentation

jasmine-dom

sloth

Custom Jasmine matchers to test the state of the DOM


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The problem

You want to use Jasmine to write tests that assert various things about the state of the 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 jasmine-dom library provides a set of custom Jasmine matchers that you can use to extend Jasmine. 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.

Using npm:

npm install --save-dev @testing-library/jasmine-dom

or for installation using yarn package manager:

yarn add --dev @testing-library/jasmine-dom

Usage

You should have a directory for helpers specified inside the helpers array in your jasmine.json file. Example:

{
	"spec_dir": "src/__tests__",
	"spec_files": ["**/*.test.js"],
	"helpers": ["helpers/**/*.js"],
	"stopSpecOnExpectationFailure": false,
	"random": false
}

Make a new file inside that directory, import @testing-library/jasmine-dom and add the matchers like so:

import JasmineDOM from '@testing-library/jasmine-dom';

beforeAll(() => {
	jasmine.getEnv().addMatchers(JasmineDOM);
});

That's it! You're good to go.

Matchers

This library is meant to be a Jasmine version of @testing-library/jest-dom library. As such, it provides the same set of matchers and the same functionality for each one, with a couple of minor diferences:

  • toBeEmpty() is not included, in favor of toBeEmptyDOMElement()
  • toBeInTheDOM() is not included, since it's deprecated
  • toContainHTML() is not included
  • toHaveClass() is renamed to toHaveClassName() to prevent name collision with Jasmine's toHaveClass()

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>
expect(getByTestId('button')).toBeDisabled()
expect(getByTestId('input')).toBeDisabled()
expect(getByText('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.


toBeEmptyDOMElement

toBeEmptyDOMElement()

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

Examples

<span data-testid="not-empty"><span data-testid="empty"></span></span>
expect(getByTestId('empty')).toBeEmptyDOMElement()
expect(getByTestId('not-empty')).not.toBeEmptyDOMElement()

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>
expect(
  getByTestId(document.documentElement, 'html-element'),
).toBeInTheDocument()
expect(
  getByTestId(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 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

<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" />

<form data-testid="valid-form">
  <input />
</form>

<form data-testid="invalid-form">
  <input required />
</form>
expect(getByTestId('no-aria-invalid')).not.toBeInvalid()
expect(getByTestId('aria-invalid')).toBeInvalid()
expect(getByTestId('aria-invalid-value')).toBeInvalid()
expect(getByTestId('aria-invalid-false')).not.toBeInvalid()

expect(getByTestId('valid-form')).not.toBeInvalid()
expect(getByTestId('invalid-form')).toBeInvalid()

toBeRequired

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

<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>
expect(getByTestId('required-input')).toBeRequired()
expect(getByTestId('aria-required-input')).toBeRequired()
expect(getByTestId('conflicted-input')).toBeRequired()
expect(getByTestId('aria-not-required-input')).not.toBeRequired()
expect(getByTestId('optional-input')).not.toBeRequired()
expect(getByTestId('unsupported-type')).not.toBeRequired()
expect(getByTestId('select')).toBeRequired()
expect(getByTestId('textarea')).toBeRequired()
expect(getByTestId('supported-role')).not.toBeRequired()
expect(getByTestId('supported-role-aria')).toBeRequired()

toBeValid

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

<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" />

<form data-testid="valid-form">
  <input />
</form>

<form data-testid="invalid-form">
  <input required />
</form>
expect(getByTestId('no-aria-invalid')).toBeValid()
expect(getByTestId('aria-invalid')).not.toBeValid()
expect(getByTestId('aria-invalid-value')).not.toBeValid()
expect(getByTestId('aria-invalid-false')).toBeValid()

expect(getByTestId('valid-form')).toBeValid()
expect(getByTestId('invalid-form')).not.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
  • if <details /> it has the open 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>
expect(getByText('Zero Opacity Example')).not.toBeVisible()
expect(getByText('Visibility Hidden Example')).not.toBeVisible()
expect(getByText('Display None Example')).not.toBeVisible()
expect(getByText('Hidden Parent Example')).not.toBeVisible()
expect(getByText('Visible Example')).toBeVisible()
expect(getByText('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>
const ancestor = getByTestId('ancestor')
const descendant = getByTestId('descendant')
const nonExistantElement = getByTestId('does-not-exist')

expect(ancestor).toContainElement(descendant)
expect(descendant).not.toContainElement(ancestor)
expect(ancestor).not.toContainElement(nonExistantElement)

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 a RegExp.

Examples

<button data-testid="ok-button" type="submit" disabled>ok</button>
const button = getByTestId('ok-button')

expect(button).toHaveAttribute('disabled')
expect(button).toHaveAttribute('type', 'submit')
expect(button).not.toHaveAttribute('type', 'button')

expect(button).toHaveAttribute('type', /sub/))
expect(button).toHaveAttribute('type', /but/))

toHaveClassName

toHaveClassName(...classNames: string[], options?: {exact: boolean})

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>
const deleteButton = getByTestId('delete-button')
const noClasses = getByTestId('no-classes')

expect(deleteButton).toHaveClassName('extra')
expect(deleteButton).toHaveClassName('btn-danger btn')
expect(deleteButton).toHaveClassName('btn-danger', 'btn')
expect(deleteButton).not.toHaveClassName('btn-link')

expect(deleteButton).toHaveClassName('btn-danger extra btn', {exact: true}) // to check if the element has EXACTLY a set of classes
expect(deleteButton).not.toHaveClassName('btn-danger extra', {exact: true}) // if it has more than expected it is going to fail

expect(noClasses).not.toHaveClassName()

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>
const input = getByTestId('element-to-focus')

input.focus()
expect(input).toHaveFocus()

input.blur()
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>
expect(getByTestId('login-form')).toHaveFormValues({
  username: 'jane.doe',
  rememberMe: true,
})

toHaveStyle

toHaveStyle(css: string | object)

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; background-color: red"
>
  Delete item
</button>
const button = getByTestId('delete-button')

expect(button).toHaveStyle('display: none')
expect(button).toHaveStyle({display: 'none'})
expect(button).toHaveStyle(`
  background-color: red;
  display: none;
`)
expect(button).toHaveStyle({
  backgroundColor: 'red',
  display: 'none',
})
expect(button).not.toHaveStyle(`
  background-color: blue;
  display: none;
`)
expect(button).not.toHaveStyle({
  backgroundColor: '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>
const element = getByTestId('text-content')

expect(element).toHaveTextContent('Content')
expect(element).toHaveTextContent(/^Text Content$/) // to match the whole content
expect(element).toHaveTextContent(/content$/i) // to use case-insensitive match
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 <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

<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 DOM Testing Library
const textInput = screen.getByTestId('input-text')
const numberInput = screen.getByTestId('input-number')
const emptyInput = screen.getByTestId('input-empty')
const selectInput = screen.getByTestId('select-number')

expect(textInput).toHaveValue('text')
expect(numberInput).toHaveValue(5)
expect(emptyInput).not.toHaveValue()
expect(selectInput).not.toHaveValue(['second', 'third'])

toHaveDisplayValue

toHaveDisplayValue(value: string | RegExp | (string|RegExp)[])

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

<label for="input-example">First name</label>
<input type="text" id="input-example" value="Luca" />

<label for="textarea-example">Description</label>
<textarea id="textarea-example">An example description here.</textarea>

<label for="single-select-example">Fruit</label>
<select id="single-select-example">
  <option value="">Select a fruit...</option>
  <option value="banana">Banana</option>
  <option value="ananas">Ananas</option>
  <option value="avocado">Avocado</option>
</select>

<label for="mutiple-select-example">Fruits</label>
<select id="multiple-select-example" multiple>
  <option value="">Select a fruit...</option>
  <option value="banana" selected>Banana</option>
  <option value="ananas">Ananas</option>
  <option value="avocado" selected>Avocado</option>
</select>
Using DOM Testing Library
const input = screen.getByLabelText('First name')
const textarea = screen.getByLabelText('Description')
const selectSingle = screen.getByLabelText('Fruit')
const selectMultiple = screen.getByLabelText('Fruits')

expect(input).toHaveDisplayValue('Luca')
expect(input).toHaveDisplayValue(/Luc/)
expect(textarea).toHaveDisplayValue('An example description here.')
expect(textarea).toHaveDisplayValue(/example/)
expect(selectSingle).toHaveDisplayValue('Select a fruit...')
expect(selectSingle).toHaveDisplayValue(/Select/)
expect(selectMultiple).toHaveDisplayValue([/Avocado/, 'Banana'])

toBeChecked

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

<input type="checkbox" checked data-testid="input-checkbox-checked" />
<input type="checkbox" data-testid="input-checkbox-unchecked" />
<div role="checkbox" aria-checked="true" data-testid="aria-checkbox-checked" />
<div
  role="checkbox"
  aria-checked="false"
  data-testid="aria-checkbox-unchecked"
/>

<input type="radio" checked value="foo" data-testid="input-radio-checked" />
<input type="radio" value="foo" data-testid="input-radio-unchecked" />
<div role="radio" aria-checked="true" data-testid="aria-radio-checked" />
<div role="radio" aria-checked="false" data-testid="aria-radio-unchecked" />
<div role="switch" aria-checked="true" data-testid="aria-switch-checked" />
<div role="switch" aria-checked="false" data-testid="aria-switch-unchecked" />
const inputCheckboxChecked = getByTestId('input-checkbox-checked')
const inputCheckboxUnchecked = getByTestId('input-checkbox-unchecked')
const ariaCheckboxChecked = getByTestId('aria-checkbox-checked')
const ariaCheckboxUnchecked = getByTestId('aria-checkbox-unchecked')
expect(inputCheckboxChecked).toBeChecked()
expect(inputCheckboxUnchecked).not.toBeChecked()
expect(ariaCheckboxChecked).toBeChecked()
expect(ariaCheckboxUnchecked).not.toBeChecked()

const inputRadioChecked = getByTestId('input-radio-checked')
const inputRadioUnchecked = getByTestId('input-radio-unchecked')
const ariaRadioChecked = getByTestId('aria-radio-checked')
const ariaRadioUnchecked = getByTestId('aria-radio-unchecked')
expect(inputRadioChecked).toBeChecked()
expect(inputRadioUnchecked).not.toBeChecked()
expect(ariaRadioChecked).toBeChecked()
expect(ariaRadioUnchecked).not.toBeChecked()

const ariaSwitchChecked = getByTestId('aria-switch-checked')
const ariaSwitchUnchecked = getByTestId('aria-switch-unchecked')
expect(ariaSwitchChecked).toBeChecked()
expect(ariaSwitchUnchecked).not.toBeChecked()

toBePartiallyChecked

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

<input type="checkbox" aria-checked="mixed" data-testid="aria-checkbox-mixed" />
<input type="checkbox" checked data-testid="input-checkbox-checked" />
<input type="checkbox" data-testid="input-checkbox-unchecked" />
<div role="checkbox" aria-checked="true" data-testid="aria-checkbox-checked" />
<div
  role="checkbox"
  aria-checked="false"
  data-testid="aria-checkbox-unchecked"
/>
<input type="checkbox" data-testid="input-checkbox-indeterminate" />
const ariaCheckboxMixed = getByTestId('aria-checkbox-mixed')
const inputCheckboxChecked = getByTestId('input-checkbox-checked')
const inputCheckboxUnchecked = getByTestId('input-checkbox-unchecked')
const ariaCheckboxChecked = getByTestId('aria-checkbox-checked')
const ariaCheckboxUnchecked = getByTestId('aria-checkbox-unchecked')
const inputCheckboxIndeterminate = getByTestId('input-checkbox-indeterminate')

expect(ariaCheckboxMixed).toBePartiallyChecked()
expect(inputCheckboxChecked).not.toBePartiallyChecked()
expect(inputCheckboxUnchecked).not.toBePartiallyChecked()
expect(ariaCheckboxChecked).not.toBePartiallyChecked()
expect(ariaCheckboxUnchecked).not.toBePartiallyChecked()

inputCheckboxIndeterminate.indeterminate = true
expect(inputCheckboxIndeterminate).toBePartiallyChecked()

toHaveDescription

toHaveDescription(text: string | RegExp)

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.

Examples

<button aria-label="Close" aria-describedby="description-close">
  X
</button>
<div id="description-close">
  Closing will discard any changes
</div>

<button>Delete</button>
const closeButton = getByRole('button', {name: 'Close'})

expect(closeButton).toHaveDescription('Closing will discard any changes')
expect(closeButton).toHaveDescription(/will discard/) // to partially match
expect(closeButton).toHaveDescription(/^closing/i) // to use case-insensitive match
expect(closeButton).not.toHaveDescription('Other description')

const deleteButton = getByRole('button', {name: 'Delete'})
expect(deleteButton).not.toHaveDescription()
expect(deleteButton).toHaveDescription('') // Missing or empty description always becomes a blank string

Inspiration

This library was heavily inspired by testing-library being jest-dom a part of its ecosystem, and Kent C. Dodds' guiding principles.

The intention is to make these matchers available to developers using Jasmine instead of Jest.

Other Solutions

I'm not aware of any, if you are please do make a PR and add it here!

For extending Jasmine's matchers outside the realm of DOM testing, Jasmine-Matchers is an option.

Guiding Principles

The more your tests resemble the way your software is used, the more confidence they can give you

Contributors

Thanks goes to these people (emoji key)

This project follows the all-contributors specification. Contributions of any kind are welcome!

LICENSE

MIT