You can get even nicer and more useful (due to generated assertion messages) with Sweet.js macros (https://github.com/andreypopp/sweet-assertions)

  describe 'when the universe exists' {
    it 'should be active' {
      universe.active should be true
    }
  }

The pre-generated assertion messages means you get `universe.active should be true` in case of error which includes actual source of the expression.