Added a test case for the variables in the JSON header
Added a test case for the variables in the JSON header

ssssam/rdflib,armandobs14/rdflib,ssssam/rdflib,ssssam/rdflib,yingerj/rdflib,RDFLib/rdflib,avorio/rdflib,armandobs14/rdflib,marma/rdflib,dbs/rdflib,armandobs14/rdflib,yingerj/rdflib,yingerj/rdflib,ssssam/rdflib,dbs/rdflib,armandobs14/rdflib,avorio/rdflib,yingerj/rdflib,RDFLib/rdflib,avorio/rdflib,avorio/rdflib,marma/rdflib,dbs/rdflib,RDFLib/rdflib,RDFLib/rdflib,marma/rdflib,dbs/rdflib,marma/rdflib