Well I see, how this should work now... All default properties in the pig namespace are going into pig-default.properties and all other defaults are getting set by setDefaultsIfUnset ?!
I still am wondering why I have no pig-default.properties in my classpath. It seems like the prebuilt jars in the 0.10.0 release are containing the pig-default.properties file, but it is missing from the PIG_HOME/conf dir, so that my custom built jars ended up missing the file and thus the tests failed. Is this known or should I file a bug?
Thanks again for clearing this up!