npm run test has 2 failing

[Angelii]

When I run the test, the console has reported an error:

  146 passing (803ms)
  2 failing

  1) Controller
       version warning [browser-only]
         should fire warning when out of date:
     Uncaught ReferenceError: window is not defined
      at Function.Dialog.warnOutOfDate (lib/dialog.js:73:21)
      at module.exports.Controller.checkOutOfDate (lib/controller.js:449:12)
      at module.exports.<anonymous> (test/controller.js:263:27)
      at module.exports.<anonymous> (lib/controller.js:349:16)
      at module.exports.BaseConnection.handleData (lib/connection/base.js:133:10)
      at module.exports.<anonymous> (test/helpers/common.js:28:18)
      at module.exports.BaseConnection.handleOpen (lib/connection/base.js:68:10)
      at Timeout._onTimeout (test/helpers/common.js:19:40)
      at listOnTimeout (internal/timers.js:557:17)
      at processTimers (internal/timers.js:500:7)

  2) Controller
       should show & hide [browser-only]:
     ReferenceError: Dialog is not defined
      at Context.<anonymous> (test/dialog.js:4:18)
      at processImmediate (internal/timers.js:464:21)

The question is：why is this window not defined?