TestEnv = function(testsDir) {
  /** @type {string} */
  this.testsDir = testsDir;

  /** @type {string} */
  this.tempPath = pathMod.resolve(new temp.Dir().path);

  /** @type {string} */
  this.origPath = process.cwd();

  /** @type {string} */
  this.genDir = pathMod.join(this.tempPath, 'gen');

  /** @type {string} */
  this.htmlDir = pathMod.join(this.tempPath, 'html');
}
@constructor
A helper class for creating a temporary directory that is capable of
executing tests.
@param {string} testsDir The folder that contains all the tests.