function testIsApproved()
 {
     $postData = $this->schemaNotification('transaction_notification.json');
     $tn = new TransactionNotification($postData);
     $this->assertTrue($tn->isApproved());
     $postData['status'] = Transaction::STATUS_DECLINED;
     $tn = new TransactionNotification($postData);
     $this->assertEqual($tn->status, 'declined');
     $this->assertFalse($tn->isApproved());
     $postData['status'] = Transaction::STATUS_ERROR;
     $tn = new TransactionNotification($postData);
     $this->assertEqual($tn->status, 'error');
     $this->assertFalse($tn->isApproved());
 }