end = function end() {
	    if (!_this2.total && _this2._opts.failZero) _this2.failures = 1;
	    debug('run(): root suite completed; emitting %s', constants$1.EVENT_RUN_END);

	    _this2.emit(constants$1.EVENT_RUN_END);
	  }
Run the root suite and invoke `fn(failures)`
on completion.

@public
@memberof Runner
@param {Function} fn - Callback when finished
@param {{files: string[], options: Options}} [opts] - For subclasses
@returns {Runner} Runner instance.