There’s nothing quite as frustrating as watching a green test suite suddenly go red again for no apparent reason. You re-run the test, and it passes. You run it again, and it fails. The logs say it’s an accessibility violation, but nothing’s changed in the code. Sound familiar?
If you’ve ever wanted to scream at your CI pipeline, you're not alone. Flaky test scripts are one of the quiet killers of team trust in automation, especially when it comes to automated accessibility testing.
I’ve been there.
Our team once spent three days debugging a set of failing accessibility tests, only to realize they were failing because the ARIA role hadn't loaded fast enough in the DOM. It wasn’t a code regression-it was timing. A race condition. Something small, but enough to send the pipeline into chaos.
It’s enough to make you question your entire test strategy. But here's the good news: flaky automated accessibility test scripts aren’t a dead end. They’re a sign. A sign that it's time to fine-tune your approach, not toss it out.
Why Are Automated Accessibility Tests So Flaky?
Before we fix flaky tests, we have to understand why they’re flaky in the first place. The cause isn’t always obvious, but there are a few common culprits.
1. Asynchronous DOM Rendering
Modern web apps are dynamic beasts. Frameworks like React, Angular, or Vue render content asynchronously. Sometimes, your accessibility test is firing before the page finishes rendering, meaning the elements it’s checking for simply aren’t there yet.
Real-life example: A test script trying to validate
aria-labelson modal components might fail if the modal hasn't rendered fully when the check runs.
The fix?
Wait strategies. Use waitFor, setTimeout, or framework-specific utilities to ensure the DOM is stable before the accessibility assertions run.
2. Non-Deterministic Data or Components
If your app loads random or user-specific content-like advertisements, user feeds, or dynamic modals, your accessibility scripts might be testing slightly different UIs every run.
Why does it fail?
Elements might be added, reordered, or hidden between test runs, causing inconsistent results even when the accessibility violations haven’t changed.
What you can do:
- Stub or mock unpredictable content during testing.
- Use deterministic test data where possible.
- Hide third-party elements from test runs when accessibility is irrelevant to their output.
3. Poor Test Isolation
Sometimes tests aren’t flaky-it’s the environment that is.
If one test changes the app state and another test relies on that state remaining unchanged, you’re introducing test interdependence. Accessibility tests, especially in end-to-end testing frameworks like Cypress or Playwright, are prone to this if not carefully scoped.
Quick tip:
Reset app state between tests. Use beforeEach() hooks or route reloading to keep each test run clean and independent.
4. Tool Limitations and False Positives
Let’s be honest: Automated accessibility tools aren’t perfect. Axe, Lighthouse, and others do a great job catching common issues, but they’re still limited by what they can see.
According to a 2023 accessibility audit by OpenDev Labs, automated tools catch about 30-40% of WCAG violations, leaving the rest for manual testing.
Some tests might throw false positives, like flagging hidden labels or misreading nested landmarks, especially in complex layouts. When these fail intermittently, they create confusion and mistrust in the tooling.
What helps:
- Review failing rules in the documentation.
- Customize rule sets where applicable.
- Supplement automation with manual accessibility checks on key flows.
How to Stabilize Your Accessibility Test Scripts
Now that we've seen why these tests fail, let’s focus on strategies that actually fix them. These aren't silver bullets, but used together, they’ll help you regain control over your test suite.
1. Use Accessibility Testing Libraries Intelligently
Axe-core, Pa11y, and Lighthouse are the backbone of most automated accessibility testing setups. But how you integrate them matters.
Smart implementation tips:
- Use a
xe.run()after your UI is fully rendered and interactive. - Avoid global
cy.injectAxe()calls if your app has conditional loading. - Group related assertions by page or component to isolate failures.
You’re not just testing a static page-you’re testing user experience. That means your script needs to behave like a real user would, with patience.
2. Defer Accessibility Checks When Needed
It’s tempting to run your accessibility suite across every single page and component right away. But that’s a recipe for bloat and instability.
Instead, try this:
- Run accessibility checks after E2E smoke tests.
- Separate smoke tests from in-depth accessibility audits.
- Build tiered test layers—basic checks for CI/CD, full audits for pre-release.
Think of it like brushing vs. deep cleaning. You don’t need to scrub every corner daily-ust the ones most people are using right now.
3. Visualize Failures with Screenshots or Logs
One of the most stressful parts of flaky tests is not knowing why they failed. You get a vague error about a missing aria-label, but no context.
That’s where visual logs or screenshots can help. Use your testing framework to take snapshots on failure or log the exact DOM structure.
Bonus tip:
Pair the test output with your screen reader to manually verify the error. Sometimes, what the tool sees and what users hear are not the same.
4. Maintain a Clean, Modular Test Suite
Your accessibility tests should be just as readable and maintainable as your code. If your test file looks like a novel, chances are it’s hiding bugs in plain sight.
Best practices:
- Break tests into small, logical units.
- Avoid repeating the same accessibility assertions in every test.
- Abstract repetitive tasks like modal loading or route navigation.
The less cluttered your test scripts, the easier it is to spot what’s really going wrong.
A Personal Lesson: From Rage-Quit to Routine
I’ll be honest, there was a point where I almost disabled accessibility tests completely. The flakiness was so disruptive, I figured we’d catch issues during manual testing anyway.
But then one day, one of our testers flagged a missing form label that could have been caught weeks earlier, if I hadn’t silenced that test.
That moment stuck with me. Accessibility isn’t a “nice-to-have.” It’s a basic requirement. And yes, automated accessibility testing can be frustrating, but with the right setup, it becomes one of the most powerful tools in your quality toolbox.
It’s not about perfection. It’s about progress-testing better today than you did yesterday.
Final Thoughts
Fixing flaky automated accessibility test scripts isn’t just about silencing errors. It’s about building a testing culture that values stability, trust, and inclusion.
It takes time. It takes patience. And it takes the willingness to step back, refactor, and reframe how you think about accessibility testing. But once you do, the payoff is more than passing-it’s delivering better, more inclusive software.
And if you’re just getting started or feeling overwhelmed? You’re not alone. Flaky scripts happen. But with smart timing, thoughtful tooling, and a little human touch, you’ll be back on track-and your users will thank you for it.
So take a breath, re-run that suite, and let’s keep pushing forward with accessibility at the center.
Top comments (0)