function testExecSendingCorrectlyFormattedOutput()
 {
     ob_start();
     $this->funcComparison->exec();
     $output = ob_get_clean();
     $this->assertTrue(strpos($output, '<table') === false, 'Output should not contain html');
 }
<?php

require __DIR__ . '/../vendor/autoload.php';
use PHPBenchmark\testing\FunctionComparison;
FunctionComparison::load()->addFunction('Short sleep', function () {
    usleep(1);
})->addFunction('Longer sleep', function () {
    usleep(10);
})->addFunction('Even longer sleep and allocating memory', function () {
    static $str = '';
    usleep(100);
    $str .= str_repeat((string) mt_rand(), 10);
})->exec();