Assert how many components a Canvas page holds in its content region, through the layout API (the published layout plus any pending change), which is the cheap check after an insert or a publish.
Examples
Then the "Landing" Canvas page should have 1 component
And the "Landing" Canvas page should have 2 components
Then the "Home" Canvas page should have at least 1 component
And the "Canvas API page" Canvas page should have at least 2 components
Then the "Empty page" Canvas page should have 0 components
Pattern
Then(/^the "([^"]*)" Canvas page should have (at least )?(\d+) components?$/, …)
Part of @webship-js/drupal-cms-steps (github.com/webship/drupal-cms-steps), a step pack for Webship-js 2.0.x.