docs: function loadFileData(fileName) {
      var testConfig = this.testConfig;
      if (!testConfig) {
          throw new Error('No test configuration found.\n' +
              'You can add one by adding a property called `testConfig` to the word object.');
      }
      var testDataRoot = testConfig.testDataRoot;
      if (!testDataRoot) {
          throw new Error('No test data root path found.\n' +
              'You can add one by adding a property called `testDataRoot` to the test configuration.');
      }
      var filePath = path.join(testDataRoot, fileName);
      this._log.trace({ path: filePath }, 'Loading file.');
  
      //Don't use `require` because that caches the returned object.
      var value = require('fs').createReadStream(filePath);
      this._log.trace({ loadedData: value }, 'File loaded.');
      return value;
  }