Contao\CoreBundle\Referer\TokenGenerator::generateToken PHP Method

    public function generateToken()
    {
        return substr(parent::generateToken(), 0, 8);
    }

 /**
  * Tests whether the generated token is eight characters long.
  */
 public function testGeneratedTokenHasLengthOfEight()
 {
     $generator = new TokenGenerator(1000);
     $this->assertEquals(8, strlen($generator->generateToken()));
 }