siblings() error: InvalidArgumentException: The current node list is empty - php

Question

I have an error in symfony2 unit testing , symfony : 2.7.1
when I use siblings() I have a the error:
InvalidArgumentException: The current node list is empty.
the twig file:
<h1>ddd</h1>
<p>ahmedghgh</p>
<ul>
<li>dddd</li>
<li>eeee</li>
<li>ffff</li>
</ul>
</p>bye</p>
<form action ="" method="GET" name ="nameForm">
<input type="text" value ="name" name="name">
<input type="submit" value ="send" name="send">
</form>
BasicControllerTest.php
<?php
/*
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*/
namespace TestingSymfony\BasicBundle\Tests\Controller;
use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
class BasicControllerTest extends WebTestCase {
public function testHelloContent() {
$client = static::createClient();
$crawler = $client->request('GET', '/helloworld');
$h1 = $crawler->filter('h1')->eq(0);
$p1 = $crawler->filter('p')->first();
$ul = $p1->siblings()->eq(0);
$l1 = $ul->children()->first();
$l2 = $ul->children()->eq(1);
$l3 = $ul->children()->last();
$p2 = $crawler->filterXPath("//p")->last();
}
}
Once I remove the siblings , all is ok and no error appeared

Answer 1

You have a typo in the twig files: check that the P tag is open and closed correclty, as follow:
<p>bye</p>
instead of
</p>bye</p>
Hope this help

Answer 2

Your filterdid not return any results as you had a typo. That is why it crashed. However, for others who did not have any typo, that's how I solved this issue, by adding a try catch.
try {
$p1 = $crawler->filter('p')->first();
} catch (\InvalidArgumentException $e) {
// Handle the current node list is empty..
}