[libvirt] libvirt domXML -> libxl_domain_config conversion testing

Hi All, I've been attempting to revive the libvirt domXML -> libxl_domain_config tests originally started by Daniel all the way back in May! https://www.redhat.com/archives/libvir-list/2014-May/msg01102.html In a reply to patch5 of the series, Ian Campbell noted that the doc produced by libxl_domain_config_to_json() may change as new config is added, defaults changed, etc. Some suggestions for coping with this included 1. json template files per libxl version 2. a new API in libvirt's json toolbox to compare json docs (with ability to control the comparison, e.g. ignore certain content) 3. make use of new functionality in Xen 4.5 such as libxl_domain_config_from_json() and libxl_domain_config_compare() Option 1 is simple-minded. Option 2 is an improvement, but a growing list of content must be ignored as additions/changes are made to the libxl_domain_config object. (Example of ignored content in this discussion - https://www.redhat.com/archives/libvir-list/2014-September/msg00627.html). In some cases, we might actually want to test some of the new content instead of ignoring it. Option 3 is promising, but doesn't help with Xen versions 4.2-4.4. Also, 4.5 is missing libxl_domain_config_compare(). After a bit of hacking on a combination of 2 and 3, I'm reconsidering 1 :-). At least for Xen 4.2-4.5. It's a simple solution that doesn't prevent testing new content in the libxl_domain_config object. Going forward, I could work on libxl_domain_config_compare() for xen-unstable/4.6, and then use option 3 to stop the template bloom. Any thoughts on this approach? Smarter options? Regards, Jim