Assert the page lists post entries — the archive/search loop rendered rows.
Classic themes wrap each entry in <article>; block themes render the Post Template block as <li class="wp-block-post …">. Both carry the classes post_class() emits, so .post catches what the tag names miss.
Examples
Then I should see post entries
And we should see post entries
Then should see post entries
Then I should not see any post entries
But we should not see any post entries
Pattern
Then(/^(I |we )*should( not)* see (?:any )?post entries$/, …)
Part of @webship-js/wordpress-steps (github.com/webship/wordpress-steps), a step pack for Webship-js 2.0.x.