Fixed python3 support and added to unit tests.

Author: j3hyde

flask_babel/__init__.py

@@ -28,7 +28,7 @@
     timezone = pytz.timezone
     UTC = pytz.UTC
 
-from flask_babel._compat import string_types
+from flask_babel._compat import string_types, text_type
 
 
 class Babel(object):
@@ -512,9 +512,9 @@ def make_json_lazy_string(func, *args, **kwargs):
     from speaklater import _LazyString
 
     class JsonLazyString(_LazyString):
-        __slots__ = _LazyString.__slots__ + ('__html__',)
         def __html__(self):
-            return unicode(self)
+            return text_type(self)
+
     return JsonLazyString(func, args, kwargs)
 
 def lazy_gettext(string, **variables):

tests/tests.py

@@ -158,9 +158,11 @@ def test_lazy_gettext(self):
         yes = lazy_gettext(u'Yes')
         with app.test_request_context():
             assert text_type(yes) == 'Ja'
+            assert yes.__html__() == 'Ja'
         app.config['BABEL_DEFAULT_LOCALE'] = 'en_US'
         with app.test_request_context():
             assert text_type(yes) == 'Yes'
+            assert yes.__html__() == 'Yes'
 
     def test_list_translations(self):
         app = flask.Flask(__name__)