A small library for handling fixtures in Mocha unit tests

fixtures.js

function Fixtures(opts) {
  var self = this;
  opts = opts || {};

  self.base = opts.base ? opts.base : "";
  self._cache = {};
  self.fixture_id = opts.fixture_id || "fixture";
  self.el;

  return {
    load: function(htmlFile, done) {
      // given an htmlFile name, try to load it from the server
      // and insert the result into a cache
      // for later injection
      var xhr = new XMLHttpRequest();
      xhr.open("GET", self.base + htmlFile);
      xhr.onload = function(e) {
        if ( this.status == 200 ) {
          self._cache[htmlFile] = this.response;
          self.last_loaded_filename = htmlFile;
          done();
        }
        else {
          done('error loading page: ' + this.status);
        }
      };
      xhr.onerror = done;

      xhr.send();
    },

    inject: function(htmlFile) {
      // if no file was requested, try the last loaded file
      if ( ! htmlFile ) htmlFile = self.last_loaded_filename;

      // but if no file was ever loaded, throw an exception
      if ( ! htmlFile ) throw "Can't inject before load";

      // Inject the fixture into the DOM under a special div
      self.el = document.getElementById(self.fixture_id);
      if ( ! self.el ) {
        self.el = document.createElement('div');
        self.el.id = self.fixture_id;
        document.body.appendChild(self.el);
      }

      self.el.innerHTML = self._cache[htmlFile];
    },

    cleanup: function() {
      // empty the fixture div
      self.el = document.getElementById(self.fixture_id);
      if ( self.el ) {
        self.el.innerHTML = '';
      }
    }
  };

}