Python3 compatibility

hepdata_validator/__init__.py

@@ -22,19 +22,21 @@
 # waive the privileges and immunities granted to it by virtue of its status
 # as an Intergovernmental Organization or submit itself to any jurisdiction.
 
+from __future__ import print_function
+from builtins import object
 import abc
 
 from .version import __version__
+from future.utils import with_metaclass
 
 __all__ = ('__version__', )
 
-class Validator(object):
+class Validator(with_metaclass(abc.ABCMeta, object)):
     """
     Provides a general 'interface' for Validator in HEPdata
     which validates schema files created with the
     JSONschema syntax http://json-schema.org/
     """
-    __metaclass__ = abc.ABCMeta
 
     messages = {}
     default_schema_file = ''
@@ -100,7 +102,7 @@ def print_errors(self, file_name):
         Prints the errors observed for a file
         """
         for error in self.get_messages(file_name):
-            print('\t', error.__unicode__())
+            print(('\t', error.__unicode__()))
 
 
 class ValidationMessage(object):

hepdata_validator/data_file_validator.py

@@ -22,6 +22,7 @@
 # waive the privileges and immunities granted to it by virtue of its status
 # as an Intergovernmental Organization or submit itself to any jurisdiction.
 
+from builtins import str
 import json
 
 import os

hepdata_validator/submission_file_validator.py

@@ -1,3 +1,4 @@
+from builtins import str
 import json
 from jsonschema import validate, ValidationError
 import os

requirements.txt

@@ -1,6 +1,7 @@
 pytest>=2.7.0
 coverage
 coveralls
+future
 pyyaml
 jsonschema
-pytest-cov
+pytest-cov

testsuite/validation_test.py

@@ -1,3 +1,4 @@
+from __future__ import print_function
 import os
 import unittest