protected function validate()
{
return Luhn::validate($this->format());
}
public function testAppendCheckDigit()
{
$appended = Luhn::appendCheckDigit($this->withoutCheckDigit);
$this->assertSame($this->withoutCheckDigit . $this->theCheckDigit, $appended);
$this->assertTrue(Luhn::validate($appended));
}
