Follow a page action of the top bar by its text, opening the "More actions" dropdown first when the action lives there. A link is followed by navigating to its target; a button is clicked.
Examples
When I choose the "Edit" action in the top bar
And I choose the "Revisions" action in the top bar
When we choose the "Delete" action in the top bar
And I choose the "Duplicate" action in the top bar
When I choose the "Edit layout" action in the top bar
Pattern
When(/^(I |we )*choose the "([^"]*)" action in the top bar$/, …)
Part of @webship-js/drupal-core-steps (github.com/webship/drupal-core-steps), a step pack for Webship-js 2.0.x.