Assert the content on the page is (or is not) published. Unpublished content carries the unpublished class and an "is unpublished" notice.
Examples
Then the content on the page should be published
Then the content on the page should be unpublished
And the content on the page should not be published
Then the content on the page should not be unpublished
And the content on the page should be published
Pattern
Then(/^the content on the page should( not)* be (published|unpublished)$/, …)
Part of @webship-js/backdrop-cms-steps (github.com/webship/backdrop-cms-steps), a step pack for Webship-js 2.0.x.