test-agent-server.js

//all require paths must be absolute -- use __dirname
var Agent = require('test-agent'),
    Apps = Agent.server,
    Suite = Agent.Suite,
    suite = new Suite({
      path: __dirname,
      testDir: 'test/marionette/',
      libDir: 'lib/marionette/'
    });

server.use(Apps.Suite, suite);