Updated with more tests and improved maintainability + readability 

JsonPath is in. 
Not sure what you meant by "Some sample documents have not been changed to the new tags
For example, https://github.com/ssabpisa/oada-test/blob/master/documents/1237.json "items" do not have like https://github.com/ssabpisa/oada-test/blob/master/documents/1241.json does."