Assert a submenu has, or does not have, an entry: the links under a top-level item such as Settings (General, Writing, Reading, Discussion, Media, Permalinks, Privacy) or Posts (All Posts, Add Post, Categories, Tags).
Examples
Then the "Settings" admin submenu should list "Permalinks"
And the "Posts" admin submenu should list "Categories"
Then the "Tools" admin submenu should list "Site Health"
And the "Settings" admin submenu should not list "Hello"
Then the "Users" admin submenu should list "Profile"
Pattern
Then(/^the "([^"]*)" admin submenu should( not)* list "([^"]*)"$/, …)
Part of @webship-js/wordpress-steps (github.com/webship/wordpress-steps), a step pack for Webship-js 2.0.x.