Adds unittest for .to_json; covers 271 and 835, both 4010 and 5010
Adds unittest for .to_json; covers 271 and 835, both 4010 and 5010

jdavisp3/TigerShark,jdavisp3/TigerShark,jdavisp3/TigerShark,jdavisp3/TigerShark