Assert the breadcrumb block (.breadcrumb) contains, or does not contain, a text. Reads the whole trail, so a parent several levels up still matches. Fails distinctly when the page has no breadcrumb at all.
Examples
Then "Home" should be in the breadcrumb
And "Administration" should be in the breadcrumb
Then the breadcrumb should contain "Reports"
And the breadcrumb should not contain "Log in"
Then "Nowhere" should not be in the breadcrumb
Pattern
Then(/^(?:"([^"]*)" should( not)* be in the breadcrumbs?|(?:the )?breadcrumbs? should( not)* contain "([^"]*)")$/, …)
Part of @webship-js/drupal-core-steps (github.com/webship/drupal-core-steps), a step pack for Webship-js 2.0.x.