Make Webflow's form endpoint refuse every submission, as it does when the form is rejected: the runtime keeps the form and shows its error message. Nothing leaves the browser. Give it before opening the page.
Examples
Given the webflow form endpoint rejects submissions
Given the form endpoint rejects submissions
Given the webflow forms endpoint rejects submissions
And the form endpoint rejects submissions
Given the webflow form endpoint rejects all submissions
Pattern
Given(/^the (?:webflow )?forms? endpoint rejects (?:all )?submissions$/, …)
Part of @webship-js/webflow-steps (github.com/webship/webflow-steps), a step pack for Webship-js 2.0.x.