public function testCheckCreditorIdentifier()
{
// Valid
$this->assertSame('DE98ZZZ09999999999', SepaUtilities::checkCreditorIdentifier('DE98ZZZ09999999999'));
// Invalid by wrong checksum
$this->assertFalse(SepaUtilities::checkCreditorIdentifier('DE98ZZZ09999999998'));
// Invalid by not allowed character
$this->assertFalse(SepaUtilities::checkCreditorIdentifier('DE98ZZÄ09999999998'));
// Valid but bad formatting
$this->assertSame('DE98ZZZ09999999999', SepaUtilities::checkCreditorIdentifier('d e98 Z ZZ 09 99 9999999'));
// Valid, ignoring the middlepart
$this->assertSame('DE98ABC09999999999', SepaUtilities::checkCreditorIdentifier('DE98abc09999999999'));
}