XML Unit
XMLUnit provides assertions that help testing code that produces XML.
... of XMLUnit 2.x if you still need APIs compatible with XMLUnit 1.x. We keep using the Sourceforge infrastructure that has served as well for many years to host forums and mailing lists.
XMLUnit for .NET 0.x is not maintained any longer.
[1] https://github.com/xmlunit
[2] https://sourceforge.net/p/xmlunit/mailman/xmlunit-general/