code: function checkSubmissionDir (mode, callback) {
    var exercise = this
  
    exercise.submission = this.args[0] // submission first arg obviously
  
  
    function failBadPath () {
      exercise.emit('fail', 'Submitted a readable directory path (please supply a path to your solution)')
      callback(null, false)
    }
  
    if (!exercise.submission)
      return failBadPath()
  
    fs.stat(exercise.submission, function (err, stat) {
      if (err)
        return failBadPath()
  
      if (!stat.isDirectory())
        return failBadPath()
  
      callback(null, true)
    })
  }
docs: simple check to see they are running a verify or run with an actual directory