code: function Barrels(sourceFolder) {
    if (!(this instanceof Barrels))
      return new Barrels(sourceFolder);
  
    // Fixture objects loaded from the JSON files
    this.data = {};
  
    // Map fixture positions in JSON files to the real DB IDs
    this.idMap = {};
  
    // The list of associations by model
    this.associations = {};
  
    // Load the fixtures
    sourceFolder = sourceFolder || process.cwd() + '/test/fixtures';
    var files = fs.readdirSync(sourceFolder);
  
    for (var i = 0; i < files.length; i++) {
      if (['.json', '.js'].indexOf(path.extname(files[i]).toLowerCase()) !== -1) {
        var modelName = path.basename(files[i]).split('.')[0].toLowerCase();
        this.data[modelName] = require(path.join(sourceFolder, files[i]));
      }
    }
  
    // The list of the fixtures model names
    this.modelNames = Object.keys(this.data);
  }
docs: Barrels module
  @param {string} sourceFolder defaults to <project root>/test/fixtures