function createBenchmark( fcn, len ) {
	var x;
	var i;

	x = [];
	for ( i = 0; i < len; i++ ) {
		x.push( floor( randu()*UNICODE_MAX ) );
	}
	return benchmark;

	/**
	* Benchmark function.
	*
	* @private
	* @param {Benchmark} b - benchmark instance
	*/
	function benchmark( b ) {
		var out;
		var i;

		b.tic();
		for ( i = 0; i < b.iterations; i++ ) {
			x[ 0 ] = floor( randu()*UNICODE_MAX );
			out = fcn.apply( null, x );
			if ( typeof out !== 'string' ) {
				b.fail( 'should return a string' );
			}
		}
		b.toc();
		if ( typeof out !== 'string' ) {
			b.fail( 'should return a string' );
		}
		b.pass( 'benchmark finished' );
		b.end();
	}
}
Creates a benchmark function.

@private
@param {Function} fcn - function to test
@param {PositiveInteger} len - array length
@returns {Function} benchmark function