function testConstructorShouldAppendRandomIdToTransactionId()
 {
     Config::setIdSeparator('___');
     $p = new PaymentRequest($this->fixture('wpf_payment_request_simple.json'));
     $p->validate();
     $this->assertEqual('WpfPayment', $p->type);
     $this->assertEqual('WpfPayment', $p->getType());
     $this->assertPattern('/^wev238f328nc___[a-f0-9]{13}/', $p->transaction_id);
 }