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tests: assert what axe checks matches our a11y audits #12699

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merged 17 commits into from
Apr 25, 2022
Merged

tests: assert what axe checks matches our a11y audits #12699

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ae02e61
tests: assert what axe checks matches our a11y audits
paulirish Jun 25, 2021
4c28f7b
adjust axe run under test
paulirish Jun 25, 2021
1e7146c
rename
paulirish Jun 25, 2021
b5f2a30
cant wait for optional chainingggg
paulirish Jun 25, 2021
8d82efa
feedback: split into two
paulirish Jun 25, 2021
10b1c49
esmodule snipe: put method on class. is there a better way tho?
paulirish Jun 25, 2021
ceefe90
Update lighthouse-core/test/gather/gatherers/accessibility-test.js
paulirish Jun 25, 2021
b18145f
Update lighthouse-core/test/gather/gatherers/accessibility-test.js
paulirish Jun 25, 2021
1adb599
Merge remote-tracking branch 'origin/axeaudittest' into axeaudittest
paulirish Jun 25, 2021
5757e80
Merge remote-tracking branch 'origin/master' into axeaudittest
paulirish Nov 30, 2021
48f1686
move to pptr
paulirish Nov 30, 2021
477d0e0
lh_root
paulirish Nov 30, 2021
bb7756d
make good
paulirish Nov 30, 2021
da573e8
expose page funcs from class static property
paulirish Dec 1, 2021
b895102
Merge remote-tracking branch 'origin/master' into axeaudittest
paulirish Apr 25, 2022
4d4f872
Merge remote-tracking branch 'origin/master' into axeaudittest
paulirish Apr 25, 2022
cf3cdd2
lint
paulirish Apr 25, 2022
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38 changes: 32 additions & 6 deletions lighthouse-core/gather/gatherers/accessibility.js
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Original file line number Diff line number Diff line change
Expand Up @@ -12,13 +12,12 @@ const axeLibSource = require('../../lib/axe.js').source;
const pageFunctions = require('../../lib/page-functions.js');

/**
* This is run in the page, not Lighthouse itself.
* axe.run returns a promise which fulfills with a results object
* containing any violations.
* @return {Promise<LH.Artifacts.Accessibility>}
* @param {Array<import('axe-core/axe').resultGroups>} resultTypes
* @param {{colorContrastEnabled: boolean}} opts
* @return {Promise<import('axe-core/axe').AxeResults>}
*/
/* c8 ignore start */
async function runA11yChecks() {
async function runAxe(resultTypes, opts = {colorContrastEnabled: true}) {
/** @type {import('axe-core/axe')} */
// @ts-expect-error - axe defined by axeLibSource
const axe = window.axe;
Expand All @@ -38,8 +37,9 @@ async function runA11yChecks() {
'wcag2aa',
],
},
resultTypes: ['violations', 'inapplicable'],
resultTypes,
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it looks like resultTypes is a bit weird. We definitely have incomplete results in our artifacts and I was very confused just noticing for the first time that 'incomplete' is not in this array :)

The docs say

The resultTypes option can be used to limit the number of nodes for a rule to a maximum of one. This can be useful for improving performance on very large or complicated pages when you are only interested in certain types of results.

After axe has processed all rules normally, it generates a unique selector for all nodes in all rules. This process can be time consuming, especially for pages with lots of nodes. By limiting the nodes to a maximum of one for result types you are not interested in, you can greatly speed up the tail end performance of axe.

so I think resultTypes can remain the same since we just need the id

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over in #12536 (comment) we also talked about the value of having passes information in the artifact as well. Could start with
passes: axeResults.passes.map(result => ({id: result.id})), like notApplicable currently does to get started on that for minimal artifact cost, apparently no additional axe time (since resultTypes wasn't limiting that anyways), and it's forward compatible if we ever need to do the full createAxeRuleResultArtifact on passes since it'll still be extending {id: string}.

That would mean only opts.colorContrastEnabled would have to be custom between the two things (and maybe wouldn't need a separate method unless folks really want it).

rules: {
// Consider http://go/prcpg for expert review of the aXe rules.
'tabindex': {enabled: true},
'accesskeys': {enabled: true},
'heading-order': {enabled: true},
Expand All @@ -60,9 +60,27 @@ async function runA11yChecks() {
// https://github.com/dequelabs/axe-core/issues/2958
'nested-interactive': {enabled: false},
'frame-focusable-content': {enabled: false},
'color-contrast': {enabled: opts.colorContrastEnabled}, // See gatherer's test for explanation
'aria-roledescription': {enabled: false},
'scrollable-region-focusable': {enabled: false},
// TODO(paulirish): create audits and enable these 3.
'input-button-name': {enabled: false},
'role-img-alt': {enabled: false},
'select-name': {enabled: false},
Comment on lines +66 to +68
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has this list changed since this pr?

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funnily enough, nope!

},
});


return axeResults;
}

/**
* Run aXe and adjust results for Lighthouse consumption
* @return {Promise<LH.Artifacts.Accessibility>}
*/
async function runA11yChecks() {
const axeResults = await runAxe(['violations', 'inapplicable']);

// axe just scrolled the page, scroll back to the top of the page so that element positions
// are relative to the top of the page
document.documentElement.scrollTop = 0;
Expand Down Expand Up @@ -137,9 +155,17 @@ class Accessibility extends FRGatherer {
axeLibSource,
pageFunctions.getNodeDetailsString,
createAxeRuleResultArtifact,
runAxe,
],
});
}

// @ts-expect-error just sending 'em right through…
static runAxeForTest(...args) {
// @ts-expect-error
return runAxe(...args);
}
}

module.exports = Accessibility;

50 changes: 50 additions & 0 deletions lighthouse-core/test/gather/gatherers/accessibility-test.js
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Expand Up @@ -32,3 +32,53 @@ describe('Accessibility gatherer', () => {
err => assert.ok(err.message.includes(error)));
});
});

describe('axe-run', () => {
/**
* @jest-environment jsdom
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is this for eslint? does it actually mutate jest's environment for the entire file? just this describe?

*/
const fs = require('fs');
const jsdom = require('jsdom');
const pageFunctions = require('../../../lib/page-functions.js');

const jdomObj = new jsdom.JSDOM(`<!doctype html><meta charset="utf8"><title>hi</title>valid.`);
let axe;

beforeAll(() =>{
// Needed by axe-core
// https://github.com/dequelabs/axe-core/blob/581c441c/doc/examples/jsdom/test/a11y.js#L24
global.window = global.self = jdomObj.window;
global.document = jdomObj.window.document;
global.getNodeDetails = pageFunctions.getNodeDetails;

// axe-core must be required after the global polyfills
axe = require('axe-core'); // eslint-disable-line no-unused-vars
});

afterAll(() => {
global.window = undefined;
global.document = undefined;
global.getNodeDetails = undefined;
});

it('tests only the checks we have audits defined for', async () => {
// The color-contrast rule is manually disabled as jsdom doesn't support the APIs needed. https://github.com/dequelabs/axe-core/blob/581c441c/doc/examples/jsdom/test/a11y.js#L40
const axeResults = await AccessibilityGather.runAxeForTest(undefined, {
colorContrastEnabled: false,
});

const axeRuleIds = new Set();
for (const type of ['violations', 'incomplete', 'inapplicable', 'passes']) {
if (axeResults[type]) axeResults[type].forEach(result => axeRuleIds.add(result.id));
}
axeRuleIds.add('color-contrast');
const axeRuleIdsArr = Array.from(axeRuleIds).sort();

// Note: audit ids match their filenames, thx to the getAuditList test in runner-test.js
const filenames = fs.readdirSync(__dirname + '/../../../audits/accessibility/')
.map(f => f.replace('.js', '')).filter(f => f !== 'axe-audit' && f !== 'manual')
.sort();

expect(axeRuleIdsArr).toEqual(filenames);
});
});