For https://github.com/xp-framework/xp-framework/pull/267#discussion_r3613149

EndsWithTest.class.php

<?php
  use \util\profiling\Timer;
  use \lang\Runtime;

  class EndsWithTest extends Object {

    public static function main($args) {
      foreach (['not-contained', 'contained'] as $needle) {
        foreach (['', 'Hello runners', file_get_contents(__FILE__), file_get_contents('README.md')] as $haystack) {
          $haystack.= 'contained';
          $t= Timer::measure(function() use($needle, $haystack) {
            $s= new String($haystack); 
            for ($i= 0; $i < 50000; $i++) { 
              $s->endsWith($needle);
            }
          });
          Console::writeLinef(
            '"%s": %d bytes: %.3f seconds, memory used: %.3f kB', 
            $needle,
            strlen($haystack), 
            $t->elapsedTime(),
            Runtime::getInstance()->memoryUsage() / 1024
          );
        }
      }
    }
  }
?>

StartsWithTest.class.php

<?php
  use \util\profiling\Timer;
  use \lang\Runtime;

  class StartsWithTest extends Object {

    public static function main($args) {
      foreach (['not-contained', 'contained'] as $needle) {
        foreach (['', 'Hello runners', file_get_contents(__FILE__), file_get_contents('README.md')] as $haystack) {
          $haystack= 'contained'.$haystack;
          $t= Timer::measure(function() use($needle, $haystack) {
            $s= new String($haystack); 
            for ($i= 0; $i < 50000; $i++) { 
              $s->startsWith($needle);
            }
          });
          Console::writeLinef(
            '"%s": %d bytes: %.3f seconds, memory used: %.3f kB', 
            $needle,
            strlen($haystack), 
            $t->elapsedTime(),
            Runtime::getInstance()->memoryUsage() / 1024
          );
        }
      }
    }
  }
?>