When I choose the "Post name" permalink structure

Choose a permalink structure on Settings > Permalinks, by the name the screen gives it: Plain, Day and name, Month and name, Numeric, Post name. Follow it with "I save the settings". The structure before the change is remembered for "I restore the permalink structure".

Examples

When I choose the "Post name" permalink structure
When we choose the "Day and name" permalink structure
And I choose the "Plain" permalink structure
When I choose the "Numeric" permalink structure
And we choose the "Month and name" permalink structure

Pattern

When(/^(I |we )*choose the "([^"]*)" permalink structure$/, …)

Part of @webship-js/wordpress-steps (github.com/webship/wordpress-steps), a step pack for Webship-js 2.0.x.