Assert the page offers (or does not offer) a page tab: the local tasks of the page, such as "View" and "Edit" on a content page.
Examples
Then I should see the "Edit" page tab
Then I should not see the "Edit" page tab
And I should see the "View" page tab
Then we should see the "Manage blocks" page tab
And should not see the "Configure layout" page tab
Pattern
Then(/^(I |we )*should( not)* see the "([^"]*)" page tab$/, …)
Part of @webship-js/backdrop-cms-steps (github.com/webship/backdrop-cms-steps), a step pack for Webship-js 2.0.x.