Axe-Playwright
Axe is an accessibility testing engine for websites and other HTML-based user interfaces. This package provides simple axe analyser commands which you can incorporate in your Playwright tests.
Install and configure
Add as a dev dependency:
npm i -D axe-playwright
Install peer dependencies:
npm i -D playwright
NOTE: axe-core is now bundled and doesn't need to be installed as a peer dependency
Add Typings
//tsconfig.json
{
"compilerOptions": {
"types": ["axe-playwright"]
}
}
Commands
injectAxe
This will inject the axe-core
runtime into the page under test. You must run this after a call to page.goto()
and before you run the checkA11y
command.
You run this command with injectAxe()
either in your test, or in a beforeEach
, as long as the visit
comes first.
beforeAll(async () => {
browser = await chromium.launch()
page = await browser.newPage()
await page.goto(`http://localhost:3000/login`)
await injectAxe(page)
})
configureAxe
Purpose
To configure the format of the data used by aXe. This can be used to add new rules, which must be registered with the library to execute.
Description
User specifies the format of the JSON structure passed to the callback of axe.run
Link - aXe Docs: axe.configure
it('Has no detectable a11y violations on load (custom configuration)', async () => {
// Configure aXe and test the page at initial load
await configureAxe(page, {
branding: {
brand: String,
application: String,
},
reporter: 'option',
checks: [Object],
rules: [Object],
locale: Object,
})
await checkA11y()
})
checkA11y
This will run axe against the document at the point in which it is called. This means you can call this after interacting with your page and uncover accessibility issues introduced as a result of rendering in response to user actions.
Parameters on checkA11y (axe.run)
page (mandatory)
The page
instance of playwright
.
context (optional)
Defines the scope of the analysis - the part of the DOM that you would like to analyze. This will typically be the document or a specific selector such as class name, ID, selector, etc.
axeOptions (optional)
Set of options passed into rules or checks, temporarily modifying them. This contrasts with axe.configure, which is more permanent.
The keys consist of those accepted by axe.run
's options argument as well as custom includedImpacts
, detailedReport
, verbose
, and detailedReportOptions
keys.
The includedImpacts
key is an array of strings that map to impact
levels in violations. Specifying this array will only include violations where the impact matches one of the included values. Possible impact values are "minor", "moderate", "serious", or "critical".
Filtering based on impact in combination with the skipFailures
argument allows you to introduce axe-playwright
into tests for a legacy application without failing in CI before you have an opportunity to address accessibility issues. Ideally, you would steadily move towards stricter testing as you address issues.
e-effects, such as adding custom output to the terminal.
NOTE: This respects the includedImpacts
filter and will only execute with violations that are included.
The detailedReport
key is a boolean whether to print the more detailed report detailedReportOptions
is an object with the shape
{
html?: boolean // include the full html for the offending nodes
}
The verbose
key is a boolean to whether to print the message No accessibility violations detected!
when there aren't accessibility violations present in the test. For the DefaultTerminalReporter
this is true and for the v2 Reporter
this is false.
skipFailures (optional, defaults to false)
Disables assertions based on violations and only logs violations to the console output. If you set skipFailures
as true
, although accessibility check is not passed, your test will not fail. It will simply print the violations in the console, but will not make the test fail.
reporter (optional)
A class instance that implements the Reporter
interface or values default
, v2
and html
. Custom reporter instances can be supplied to override default reporting behaviour dictated by DefaultTerminalReporter
set by the value default
. v2
is the new TerminalReporter inspired by the reports from jest-axe. html
reporter will generate external HTML file.
Note! html
reporter will disable printed to logs violations.
options (dedicated for axe-html-reporter)
Options dedicated for HTML reporter. axe-html-reporter
getAxeResults
This will run axe against the document at the point in which it is called, then returns the full set of results as reported by axe.run
.
Parameters on getAxeResults
page (mandatory)
The page
instance of playwright
.
context (optional)
Defines the scope of the analysis - the part of the DOM that you would like to analyze. This will typically be the document or a specific selector such as class name, ID, selector, etc.
options (optional)
Set of options passed into rules or checks, temporarily modifying them. This contrasts with axe.configure, which is more permanent.
The object is of the same type which is accepted by axe.run
's options argument and directly forwarded to it.
getViolations
This will run axe against the document at the point in which it is called, then return you an array of accessibility violations (i.e. the violations
array included in the getAxeResults
result).
Parameters on getViolations (axe.run)
Identical to parameters of getAxeResults.
reportViolations
Reports violations based on the Reporter
concrete implementation behaviour.
Parameters on reportViolations
violations (mandatory)
An array of Axe violations to be printed.
reporter (mandatory)
A class instance that implements the Reporter
interface. Custom reporter instances can be supplied to override default reporting behaviour dictated by DefaultTerminalReporter
.
Examples
Basic usage
import { chromium, Browser, Page } from 'playwright'
import { injectAxe, checkA11y, getViolations, reportViolations } from 'axe-playwright'
let browser: Browser
let page: Page
describe('Playwright web page accessibility test', () => {
beforeAll(async () => {
browser = await chromium.launch()
page = await browser.newPage()
await page.goto(`file://${process.cwd()}/test/site.html`)
await injectAxe(page)
})
it('simple accessibility run', async () => {
await checkA11y(page)
})
it('check a11y for the whole page and axe run options', async () => {
await checkA11y(page, null, {
axeOptions: {
runOnly: {
type: 'tag',
values: ['wcag2a'],
},
},
})
})
it('check a11y for the specific element', async () => {
await checkA11y(page, 'input[name="password"]', {
axeOptions: {
runOnly: {
type: 'tag',
values: ['wcag2a'],
},
},
})
})
it('gets and reports a11y for the specific element', async () => {
const violations = await getViolations(page, 'input[name="password"]', {
runOnly: {
type: 'tag',
values: ['wcag2a'],
},
})
reportViolations(violations, new YourAwesomeCsvReporter('accessibility-report.csv'))
expect(violations.length).toBe(0)
})
afterAll(async () => {
await browser.close()
})
})
This custom logging behavior results in terminal output like this:
Detailed Report
The detailed report is disabled by default, but can be enabled by including the detailedReport
property in the checkAlly
options.
import { chromium, Browser, Page } from 'playwright'
import { injectAxe, checkA11y } from 'axe-playwright'
let browser: Browser
let page: Page
describe('Playwright web page accessibility test', () => {
beforeAll(async () => {
browser = await chromium.launch()
page = await browser.newPage()
await page.goto(`file://${process.cwd()}/test/site.html`)
await injectAxe(page)
})
// Prints outs a detailed report per node with an array of numbers of which violations from the summary affect that node
it('print out a detailed report on violations', async () => {
await checkA11y(page, null, {
detailedReport: true,
})
})
// Same as above, but includes the html of the offending node
it('print out a detailed report on violations', async () => {
await checkA11y(page, null, {
detailedReport: true,
detailedReportOptions: { html: true },
})
})
afterAll(async () => {
await browser.close()
})
})
HTML Report
Thanks to axe-html-reporter you can generate HTML report(s).
From default HTML file(s) will be generated under /artifacts/accessibilityReport.html
.
Report's options can customized from checkAlly
level:
await checkA11y(
page,
'form',
{
axeOptions: {
runOnly: {
type: 'tag',
values: ['wcag2a'],
},
},
},
true, 'default',
{
outputDirPath: 'results',
outputDir: 'accessibility',
reportFileName: 'accessibility-audit.html'
}
)
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