Phpunit and autoloader

Question

I am trying to use autoloader with phpunit as follows:

• in phpunit.xml I put bootstrap="bootstrap.php"

• in bootstrap.php I put

  define( 'TESTING', true );
  putenv( 'APPLICATION_ENV=testing' );
  
  
  function __autoload($className) {    
      include_once __autoloadFilename($className);
  }
  
  
  function __autoloadFilename($className) {
      return str_replace('_','/',$className).".php";
  }
  

When I try to run the phpunit command, I get an error:

Generating code coverage report, this may take a moment.
Fatal error: Method PEAR_Autoloader::__call() must take exactly 2 arguments in /usr/share/php/PEAR/Autoloader.php on line 211

Thanks for any help.