Add some tests for the new error string representations
Add some tests for the new error string representations

eodolphi/jsonschema,jamesmarva/jsonschema,dnephin/jsonschema,Julian/jsonschema,Julian/jsonschema,python-jsonschema/jsonschema,mathewmarcus/jsonschema,eodolphi/jsonschema,varunarya10/jsonschema,sightmachine/jsonschema