Assert the page was hydrated without (or, to prove the check, with) hydration errors. React reports a mismatch between the HTML of the server and the first browser render as an error (#418, #423, #425 in production); the step waits for hydration, then reads the errors recorded since the scenario started.
Examples
Then there should be no hydration errors
And there should be no hydration errors
But there should be hydration errors
Then there should be no hydration errors
And there should be hydration errors
Pattern
Then(/^there should be (no )?hydration errors$/, …)
Part of @webship-js/gatsby-steps (github.com/webship/gatsby-steps), a step pack for Webship-js 2.0.x.