/**
* Get all valid identifiers as an associative array.
*
* @return array
*/
protected function getIdentifiers()
{
$ids = [];
if ($this->isbn && $this->isbn->isValid()) {
$ids['isbn'] = $this->isbn;
}
if ($this->issn && strlen($this->issn) == 8) {
$ids['issn'] = $this->issn;
}
if ($this->oclc && strlen($this->oclc) > 0) {
$ids['oclc'] = $this->oclc;
}
if ($this->upc && strlen($this->upc) > 0) {
$ids['upc'] = $this->upc;
}
return $ids;
}
/**
* Test Invalid ISBN-10.
*
* @return void
*/
public function testInvalidISBN10()
{
// Invalid ISBN-10:
$isbn = new ISBN('2314346323');
$this->assertFalse($isbn->get10());
$this->assertFalse($isbn->get13());
$this->assertFalse($isbn->isValid());
}