Assert a module is (or is not) the active one: its link in the module menu carries modulemenu-action-active.
Examples
Then the "Page" module should be active
And the "List" module should not be active
Then the "List" module should be active
And the "Dashboard" module should not be active
Then the "web_layout" module should be active
Pattern
Then(/^the "([^"]*)?" module should( not)* be active$/, …)
Part of @webship-js/typo3-steps (github.com/webship/typo3-steps), a step pack for Webship-js 2.0.x.