This video shows how collective.cover can be tried out by firing up only its functional test fixture.
Best Plone add-ons come with extensive test suites, which include one or more functional test fixtures. A development server called "robot-server" included in plone.app.robotframwork allows to start a volatile demo Plone site quickly with just firing up that development fixture. The demo site will contain everything that's configured in the fixture, and when the server is shut down, the site is cleaned up and gone.
See also the second part for automatic code re-loading: • Fixing Plone add-on bugs with instant code...
And the related blog post: http://datakurre.pandala.org/2013/05/...