text: // Return mock hexo for unit testing.
  exports.create = function () {
    var mock = {};
    mock.setValues =
    {
      registeredType: null,
      receivedPosts: [],
      registeredFunction: null,
      calledType: null
    };
    mock.extend = {};
    mock.extend.migrator = {};
    mock.extend.migrator.register = function (type, f) {
      mock.setValues.registeredType = type;
      mock.setValues.registeredFunction = f;
    };
    mock.call = function (type, args, callback) {
      mock.setValues.calledType = args._.shift();
      mock.setValues.registeredFunction(args, callback);    
    };
    mock.log = {
      i: function () { },
      w: function () { }
    };
    mock.post = {
      create: function (newPost, next) {
        mock.setValues.receivedPosts.push(newPost);
        next();
      }
    };
    return mock;
  };