Look for the DAV: namespace (it may not be the first), and allow resolving other namespaces.

[inferiorhumanorgans]

Apple's AddressBook.app sends out XML like this:

<?xml version="1.0" encoding="utf-8"?>
  <x0:propfind xmlns:x1="http://calendarserver.org/ns/" xmlns:x0="DAV:" xmlns:x3="http://apple.com/ns/ical/" xmlns:x2="urn:ietf:params:xml:ns:caldav">
    <x0:prop><x1:getctag/></x0:prop>
  </x0:propfind>

Which doesn't match the xpath query for a propfind as x0 isn't DAV:. This pulls the first DAV: namespace.

[chrisroberts]

I have been hacking on the prop bits quite a lot lately as I'm working on getting dav4rack through that section of the litmus. Let me test this a bit against what I have locally before I merge this in.

[inferiorhumanorgans]

Interesting. Have you seen anything similar for testing CardDAV compliance? Right now I'm kinda stalled writing some sort of test harness and it's ugly (rspec + xsd + xslt). This is the XML that was tripping me up:

<?xml version="1.0" encoding="utf-8"?>
  <x0:propfind xmlns:x1="http://calendarserver.org/ns/" xmlns:x0="DAV:" xmlns:x3="http://apple.com/ns/ical/" xmlns:x2="urn:ietf:params:xml:ns:caldav">
    <x0:prop>
      <x1:getctag/>
    </x0:prop>
  </x0:propfind>

[chrisroberts]

I'm out of time to hack on this stuff until tomorrow, but I'll use that to run some tests against and see what I get.