def _testErrors(self, schema_file, instance_file, id):
su = SU()
xfm = XFM()
xsd_file_name = os.path.join(os.path.dirname(__file__),schema_file)
xml_file_name = os.path.join(os.path.dirname(__file__),instance_file)
schema = xfm._add_schema_from_file(xsd_file_name)
formdef = su.get_formdef_from_schema_file(xsd_file_name)
data_tree = su._get_data_tree_from_file(xml_file_name)
populator = XFormDBTablePopulator( formdef, schema )
queries = populator.populate( data_tree )
xfm.remove_schema(schema.id)
return populator.errors
