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    <h3>Editing: GroupCollection.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php declare(strict_types=1);
/*
 * This file is part of PHPUnit.
 *
 * (c) Sebastian Bergmann &lt;sebastian@phpunit.de&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace PHPUnit\TextUI\XmlConfiguration;

use IteratorAggregate;

/**
 * @internal This class is not covered by the backward compatibility promise for PHPUnit
 *
 * @psalm-immutable
 *
 * @template-implements IteratorAggregate&lt;int, Group&gt;
 */
final class GroupCollection implements IteratorAggregate
{
    /**
     * @var Group[]
     */
    private $groups;

    /**
     * @param Group[] $groups
     */
    public static function fromArray(array $groups): self
    {
        return new self(...$groups);
    }

    private function __construct(Group ...$groups)
    {
        $this-&gt;groups = $groups;
    }

    /**
     * @return Group[]
     */
    public function asArray(): array
    {
        return $this-&gt;groups;
    }

    /**
     * @return string[]
     */
    public function asArrayOfStrings(): array
    {
        $result = [];

        foreach ($this-&gt;groups as $group) {
            $result[] = $group-&gt;name();
        }

        return $result;
    }

    public function isEmpty(): bool
    {
        return empty($this-&gt;groups);
    }

    public function getIterator(): GroupCollectionIterator
    {
        return new GroupCollectionIterator($this);
    }
}
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