cs: Switch to a stricter way of coding - this might break in a lot of places.

src/Bundle/ChillPersonBundle/Tests/Entity/PersonTest.php

@@ -7,6 +7,15 @@
  * the LICENSE file that was distributed with this source code.
  */
 
+declare(strict_types=1);
+
+/**
+ * Chill is a software for social workers.
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
 namespace Chill\PersonBundle\Tests\Entity;
 
 use Chill\PersonBundle\Entity\AccompanyingPeriod;
@@ -23,7 +32,7 @@ use DateTimeImmutable;
  * @internal
  * @coversNothing
  */
-class PersonTest extends \PHPUnit\Framework\TestCase
+final class PersonTest extends \PHPUnit\Framework\TestCase
 {
     /**
      * Test if the getAccompanyingPeriodsOrdered function, for periods