core(audits): remove audio-caption accessibility audit

[beaufortfrancois]

This PR removes the audio caption accessibility audit from Lighthouse as it has been disabled/deprecated since 2018. See dequelabs/axe-core#1071

Note that a web.dev PR is in progress to remove https://web.dev/audio-caption as well.

[patrickhulce]

Thanks @beaufortfrancois! Right in time for 6.0 breaking change too :)

For tests to pass you'll also need to update

lighthouse/lighthouse-core/scripts/i18n/collect-strings.js

Line 573 in 40a187f

assert.equal(collisions, 17, `The number of duplicate strings have changed, update this assertion if that is expected, or reword strings. Collisions: ${collisionStrings}`);

and our smoke test assertions
https://github.com/GoogleChrome/lighthouse/blob/master/lighthouse-cli/test/smokehouse/test-definitions/a11y/expectations.js

[patrickhulce]

I think we're still running this audit because of its wcag2a tag though, so I think we'll want to explicitly say enabled: false in our accessibility gatherer.

lighthouse/lighthouse-core/gather/gatherers/accessibility.js

Lines 34 to 51 in 40a187f

	rules: {
	'tabindex': {enabled: true},
	'accesskeys': {enabled: true},
	'heading-order': {enabled: true},
	'meta-viewport': {enabled: true},
	'duplicate-id': {enabled: false},
	'table-fake-caption': {enabled: false},
	'td-has-header': {enabled: false},
	'marquee': {enabled: false},
	'area-alt': {enabled: false},
	'aria-dpub-role-fallback': {enabled: false},
	'html-xml-lang-mismatch': {enabled: false},
	'blink': {enabled: false},
	'server-side-image-map': {enabled: false},
	'identical-links-same-purpose': {enabled: false},
	'no-autoplay-audio': {enabled: false},
	'svg-img-alt': {enabled: false},
	},

[patrickhulce]

cc @robdodson I'm assuming you're already looped in here, but any thoughts on audits/axe-rules we should be adding to be the spiritual successor here?

[connorjclark]

Note that a web.dev PR is in progress to remove web.dev/audio-caption as well.

Shouldn't we keep it, but just add a deprecated banner?

[patrickhulce]

thanks @beaufortfrancois ! in addition to @connorjclark 's web.dev comment (👍) , a heads up that there are still some failing smoketests that will need assertion updates in https://github.com/GoogleChrome/lighthouse/blob/master/lighthouse-cli/test/smokehouse/test-definitions/a11y/expectations.js

[robdodson]

cc @robdodson I'm assuming you're already looped in here, but any thoughts on audits/axe-rules we should be adding to be the spiritual successor here?

I don't think they've created a replacement for this specific audit. They do have some newer audits that seem cool like no-autoplay-audio. Their list of audits is here for what it's worth. If any of them seem interesting for Lighthouse we can try to get some docs written on the web.dev side.

[patrickhulce]

Friendly ping here @beaufortfrancois to see if you think you'll have time to get to this. We'd love to get it in before 6.0 final since it's a breaking change :)

[robdodson]

btw the recommendation on the web.dev side was to add a banner to the article stating that the audit is deprecated. Similar to what we did with heading-level. That's the easiest solution that doesn't cause us to 404 or redirect an existing url.

[beaufortfrancois]

I've added the banner to the web.dev audit article.
I'm failing to understand what needs to be done in this PR to fix tests sadly. Any help?

[patrickhulce]

This PR removed some nodes in lighthouse-cli/test/fixtures/a11y/a11y_tester.html which shifts the position of all following nodes in the tree. We need to update the test expectations in lighthouse-cli/test/smokehouse/test-definitions/a11y/expectations.js to match the new values. The new expected values are printed in the error message in travis.

[brendankenny]

thanks for wading through all 30 things that need to be updated just to remove a single audit @beaufortfrancois!

[brendankenny]

@patrickhulce not trying to steal your review :)

[patrickhulce]

LGTM too, thanks for sticking with this @beaufortfrancois!

[beaufortfrancois]

:)