Add unit test for unicode in object __repr__

This adds a unit test for the behavior when an object has a unicode
string field. If on python 2, the repr is encoded to the default
encoding (ascii) before being returned. This is to ensure calls like
str(obj_repr) will work under python 2.

This patch also adjusts logic to make the code compatbile for Python 4.

[1] http://astrofrog.github.io/blog/2016/01/12/stop-writing-python-4-incompatible-code/



Co-Authored-By: melanie witt <melwittt@gmail.com>
Change-Id: I65dd271ac2198b384d201349607e74992c447f75

oslo_versionedobjects/base.py

@@ -314,7 +314,7 @@ class VersionedObject(object):
                                   field.stringify(getattr(self, name)) or
                                   '<?>'))
                       for name, field in sorted(self.fields.items())]))
-        if not six.PY3:
+        if six.PY2:
             repr_str = encodeutils.safe_encode(repr_str, incoming='utf-8')
         return repr_str
 

oslo_versionedobjects/tests/test_objects.py

@@ -1200,6 +1200,20 @@ class _TestObject(object):
         obj2 = MySensitiveObj()
         self.assertEqual('MySensitiveObj(data=<?>)', repr(obj2))
 
+    def test_obj_repr_unicode(self):
+        obj = MyObj(bar=u'\u0191\u01A1\u01A1')
+        # verify the unicode string has been encoded as ASCII if on python 2
+        if six.PY2:
+            self.assertEqual("MyObj(bar='\xc6\x91\xc6\xa1\xc6\xa1',foo=<?>,"
+                             "missing=<?>,mutable_default=<?>,readonly=<?>,"
+                             "rel_object=<?>,rel_objects=<?>,timestamp=<?>)",
+                             repr(obj))
+        else:
+            self.assertEqual("MyObj(bar='\u0191\u01A1\u01A1',foo=<?>,"
+                             "missing=<?>,mutable_default=<?>,readonly=<?>,"
+                             "rel_object=<?>,rel_objects=<?>,timestamp=<?>)",
+                             repr(obj))
+
     def test_obj_make_obj_compatible_with_relationships(self):
         subobj = MyOwnedObject(baz=1)
         obj = MyObj(rel_object=subobj)