code: function run() {
  	var len = series.length,
  		ctx = context(),
  		i = 0;
  
  	series[ i ].call( ctx, next );
  
  	function next() {
  		i += 1;
  		if ( i < len ) {
  			series[ i ].call( ctx, next );
  		}
  	}
  }
docs: RUN // 
  FUNCTION: run()
  Runs a single test.
  
  @private