Scrats is an automated testing framework for testing how well web pages can be used by screenreaders. It's most similar to tools like Behat but instead of "using javascript to simulate user input over a slow and buggy remote protocol", scrats gives you access to a standard testing framework Mocha where you can write javascript tests against the browser accessibility tree exposed by the Chrome automation API.
Expectations can be written in a nice declarative syntax thanks to Expect.js and the test results are reported with the Test Anything Protocol so they can be easily hooked into an existing continuous integration workflow.
See Installation and Getting Started for next steps.