Faker\Generator::addProvider PHP Method

    public function addProvider($provider)
    {
        array_unshift($this->providers, $provider);
    }

 public function testBirthNumber()
 {
     $faker = new Generator();
     $faker->addProvider(new Person($faker));
     $faker->addProvider(new Miscellaneous($faker));
     for ($i = 0; $i < 1000; $i++) {
         $birthNumber = $faker->birthNumber();
         $birthNumber = str_replace('/', '', $birthNumber);
         // check date
         $year = intval(substr($birthNumber, 0, 2), 10);
         $month = intval(substr($birthNumber, 2, 2), 10);
         $day = intval(substr($birthNumber, 4, 2), 10);
         // make 4 digit year from 2 digit representation
         $year += $year < 54 ? 2000 : 1900;
         // adjust special cases for month
         if ($month > 50) {
             $month -= 50;
         }
         if ($year >= 2004 && $month > 20) {
             $month -= 20;
         }
         $this->assertTrue(checkdate($month, $day, $year), "Birth number {$birthNumber}: date {$year}/{$month}/{$day} is invalid.");
         // check CRC if presented
         if (strlen($birthNumber) == 10) {
             $crc = intval(substr($birthNumber, -1), 10);
             $refCrc = intval(substr($birthNumber, 0, -1), 10) % 11;
             if ($refCrc == 10) {
                 $refCrc = 0;
             }
             $this->assertEquals($crc, $refCrc, "Birth number {$birthNumber}: checksum {$crc} doesn't match expected {$refCrc}.");
         }
     }
 }