Handle XML errors

[pierre]

CyberSource XML parse error. errors should probably be handled as CANCELED transactions.

[pierre]

More generally, we should get the full list of possible FaultCode and categorize them appropriately (see also #5). I couldn't find any documentation on it though.

[SquareMike]

I think this document would facilitate categorization of the response codes. I am thinking of picking this issue up.

https://support.cybersource.com/cybskb/index?page=content&id=C156

[pierre]

@SquareMike Note that business-level errors are already handled, see:

• https://github.com/killbill/killbill-cybersource-plugin/blob/master/lib/cybersource/models/response.rb#L9-L10
• https://github.com/killbill/killbill-cybersource-plugin/blob/master/spec/cybersource/remote/integration_spec.rb#L479-L491

This ticket is about XML errors and generic faults. We already handle most of them:

• https://github.com/killbill/killbill-cybersource-plugin/blob/master/spec/cybersource/remote/integration_spec.rb#L434-L443
• https://github.com/killbill/killbill-cybersource-plugin/blob/master/spec/cybersource/base_plugin_spec.rb#L171-L186

but this logic could probably be improved.