Assert core's asset pipeline delivered its settings payload — the drupal-settings-json script tag, and the drupalSettings object core's JavaScript builds from it. A page that renders but never initialises this is a page whose aggregated JavaScript never arrived.
Examples
Then the core JavaScript settings should be initialized
And the core JavaScript settings should be initialized
Then the core JavaScript settings should not be initialized
And the core JavaScript settings should not be initialized
Then the core javascript settings should be initialized
Pattern
Then(/^the core (?:JavaScript|javascript) settings should( not)* be initialized$/, …)
Part of @webship-js/drupal-core-steps (github.com/webship/drupal-core-steps), a step pack for Webship-js 2.0.x.