Handle accessibility incomplete and violations simultaneously #14354
Description
FAQ
- Yes, my issue is not about variability or throttling.
[ ] Yes, my issue is not about a specific accessibility audit (file with axe-core instead).
URL
What happened?
The bypass audit based on Axe’s bypass rule always shows as passing when it’s applicable, even when there are issues on the page that Axe itself detects.
Lighthouse results for bypass on this page (JSON export)
"bypass": {
"id": "bypass",
"title": "The page contains a heading, skip link, or landmark region",
"description": "Adding ways to bypass repetitive content lets keyboard users navigate the page more efficiently. [Learn more](https://web.dev/bypass/).",
"score": 1,
"scoreDisplayMode": "binary",
"details": {
"type": "table",
"headings": [],
"items": []
}
},Axe CLI results for the same page
Command:
axe -r bypass https://accessibility-experiments-90d5b5.netlify.app/lighthouse-bypass-audit/index.html --save bypass.json && cat bypass.jsonOutput:
[
{
"testEngine": {
"name": "axe-core",
"version": "4.3.5"
},
"testRunner": {
"name": "axe"
},
"testEnvironment": {
"userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) HeadlessChrome/104.0.5112.101 Safari/537.36",
"windowWidth": 800,
"windowHeight": 600,
"orientationAngle": 0,
"orientationType": "landscape-primary"
},
"timestamp": "2022-09-03T10:13:28.251Z",
"url": "https://accessibility-experiments-90d5b5.netlify.app/lighthouse-bypass-audit/index.html",
"toolOptions": {
"runOnly": {
"type": "rule",
"values": [
"bypass"
]
},
"reporter": "v1"
},
"inapplicable": [],
"passes": [],
"incomplete": [
{
"id": "bypass",
"impact": "serious",
"tags": [
"cat.keyboard",
"wcag2a",
"wcag241",
"section508",
"section508.22.o"
],
"description": "Ensures each page has at least one mechanism for a user to bypass navigation and jump straight to the content",
"help": "Page must have means to bypass repeated blocks",
"helpUrl": "https://dequeuniversity.com/rules/axe/4.3/bypass?application=webdriverjs",
"nodes": [
{
"any": [
{
"id": "internal-link-present",
"data": null,
"relatedNodes": [],
"impact": "serious",
"message": "No valid skip link found"
},
{
"id": "header-present",
"data": null,
"relatedNodes": [],
"impact": "serious",
"message": "Page does not have a heading"
},
{
"id": "landmark",
"data": null,
"relatedNodes": [],
"impact": "serious",
"message": "Page does not have a landmark region"
}
],
"all": [],
"none": [],
"impact": "serious",
"html": "<html lang=\"en\" class=\"deque-axe-is-ready\">",
"target": [
"html"
],
"failureSummary": "Fix any of the following:\n No valid skip link found\n Page does not have a heading\n Page does not have a landmark region"
}
]
}
],
"violations": []
}
]What did you expect?
Lighthouse’s results for bypass should be consistent with those of Axe. In this instance, Axe reports bypass as "incomplete", so it shouldn’t be a pass with Lighthouse. I would have expected either a "Additional items to manually check", or an error.
What have you tried?
I’ve investigated how the Axe rule works, and suspect the issue is due to Axe changing the output of this rule from violations to incomplete. This apparently happened in Axe v4.2 because although the rule can detect the absence of "bypass" functionality, it can’t detect whether there is actually anything to bypass on a page.
I suspect the issue in Lighthouse is in the Axe audit processing logic, around here, where Axe handles incomplete results differently based on the audit’s display mode:
lighthouse/core/audits/accessibility/axe-audit.js
Lines 47 to 58 in fd304ed
I’m unclear whether the current logic could work or whether there needs to be additions here.
How were you running Lighthouse?
Chrome DevTools, web.dev
Lighthouse Version
9.6.6
Chrome Version
107
Node Version
No response
OS
Mac
Relevant log output
No response