mattt/Ono — pull request #20 by erikprice (2014-07-16 19:38:36+00:00)
Title: Failing test for XPath namespace query in VMAP document

:warning: **THIS PULL REQUEST NOT INTENDED FOR MERGE** :warning:

I'm observing some strange behavior using the Ono library. (To be completely fair, it actually seems to be a problem in libxml2.) This PR isn't so much intended to be merged, as it is to show the strange/buggy behavior.

The problem is that the `-[ONOXMLDocument XPath:]` method fails for the `/vmap:VMAP/vmap:Extensions/uo:unicornOnce` XPath query against the following XML document:

```xml

```

Yet, it works for the following document, which is identical to the above, except in the order in which namespace attribute declarations appear in the root element:

```xml

```

The root of the problem seems to be that the ONOXMLDocument's `self.xmlNode` doesn't have the `uo` namespace when it calls `xmlXPathRegisterNs()`.

Am I misunderstanding something about XML documents or XML namespaces, or is this a legitimate bug?