Assert that the edit form shows, or does not show, the notice of unsaved changes: the changes it stored in the background and that are not yet part of the saved element.
Examples
Then I should see the unsaved changes notice
Then I should not see the unsaved changes notice
Then we should see the unsaved changes notice
And I should not see the unsaved changes notice
And we should see the unsaved changes notice
Pattern
Then(/^(I |we )*should( not)* see the unsaved changes notice$/, …)
Part of @webship-js/craft-cms-steps (github.com/webship/craft-cms-steps), a step pack for Webship-js 2.0.x.