PhpSpec\Locator\PSR0\PSR0Resource::getSrcFilename PHP Method

    public function getSrcFilename()
    {
        if ($this->locator->isPSR4()) {
            return $this->locator->getFullSrcPath() . implode(DIRECTORY_SEPARATOR, $this->parts) . '.php';
        }
        $nsParts = $this->parts;
        $classname = array_pop($nsParts);
        $parts = array_merge($nsParts, explode('_', $classname));
        return $this->locator->getFullSrcPath() . implode(DIRECTORY_SEPARATOR, $parts) . '.php';
    }

 protected function is(PSR0Resource $resource, $tag)
 {
     $tokens = $this->filesystem->getTokens($resource->getSrcFilename());
     foreach ($tokens as $token) {
         if (is_array($token) && current($token) === $tag) {
             return true;
         }
     }
     return false;
 }