Checks if a PHP sourcefile is readable. The sourcefile is loaded through the load() method.
string $filename:
public static function checkAndLoad($filename) {
$includePathFilename = stream_resolve_include_path($filename);
if (!$includePathFilename || !is_readable($includePathFilename)) {
throw new PHPUnit_Framework_Exception(sprintf('Cannot open file "%s".' . "\n", $filename));
}
self::load($includePathFilename);
return $includePathFilename;
}