[py3] Refactored __unicode__ to __str__.

* Renamed the __unicode__ methods
* Applied the python_2_unicode_compatible decorator
* Removed the StrAndUnicode mix-in that is superseded by
  python_2_unicode_compatible
* Kept the __unicode__ methods in classes that specifically
  test it under Python 2

1 files changed, 3 insertions, 1 deletions

diff --git a/tests/modeltests/field_defaults/models.py b/tests/modeltests/field_defaults/models.py
index 18840c8b4b..c99d4871cd 100644
--- a/tests/modeltests/field_defaults/models.py
+++ b/tests/modeltests/field_defaults/models.py
@@ -13,11 +13,13 @@ field.
 from datetime import datetime
 
 from django.db import models
+from django.utils.encoding import python_2_unicode_compatible
 
 
+@python_2_unicode_compatible
 class Article(models.Model):
     headline = models.CharField(max_length=100, default='Default headline')
     pub_date = models.DateTimeField(default=datetime.now)
 
-    def __unicode__(self):
+    def __str__(self):
         return self.headline