How can I safely check is node empty or not? (Symfony 2 Crawler)

Have you tried something like this?

$text = null;
if (!empty($body = $crawler->filter('.PropertyBody'))) {
    if (!empty($node = $body->eq(2))) {
        $text = $node->text();
    }
}

$this->assertContains('yourText', $text);

$marks = $crawler->filter('.PropertyBody')->count()
    ? $crawler->filter('.PropertyBody')->eq(2)->text() 
    : '';