PHPUnit and Virtualbox / Uncaught exception 'PHPUnit_Framework_Exception'

testSuiteLoaderClass="PHPUnit_Runner_StandardTestSuiteLoader"

PHP Fatal error:  Uncaught exception 'PHPUnit_Framework_Exception' with message 'Neither "FooTests.php" nor "FooTests.php" could be opened.' in /usr/share/php/PHPUnit/Util/Skeleton/Test.php:102

/**
 * @return File_Iterator
 */
public function collectTests()
{
    $iterator = File_Iterator_Factory::getFileIterator(
      $this->paths, $this->suffixes, $this->prefixes
    );

    if ($this->filterIterator !== NULL) {
        $class    = new ReflectionClass($this->filterIterator);
        $iterator = $class->newInstance($iterator);
    }

    return $iterator;
}

public function collectTests()
{
    $tests = array();

    foreach ($this->paths as $path) {
        $tests = array_merge($tests, $this->_iterate($path));
    }

    return $tests;
}

protected function _iterate($path)
{
    $a = array();
    if ($h = opendir($path)) {
        while (false !== ($fname = readdir($h))) {
            $fullPath = $path . '/' . $fname;

            if ($fname == '.' || $fname == '..') {
                continue;
            }

            if (is_dir($fullPath)) {
                $a = array_merge($a, $this->_iterate($fullPath));
                continue;
            }

            foreach ((array) $this->suffixes as $sfx) {
                if (substr($fname, -strlen($sfx)) == $sfx) {
                    $a[] = $fullPath;
                    continue;
                }
            }

            foreach ((array) $this->prefixes as $pfx) {
                if (substr($fname, 0, strlen($pfx)) == $pfx) {
                    $a[] = $fullPath;
                    continue;
                }
            }
        }
        closedir($h);
    }
    return $a;
}