Only use test import munging prior to Django 1.6's new test runner

rest_framework/tests/tests.py

@@ -4,11 +4,13 @@ runner to pick up the tests.  Yowzers.
 """
 from __future__ import unicode_literals
 import os
+import django
 
 modules = [filename.rsplit('.', 1)[0]
            for filename in os.listdir(os.path.dirname(__file__))
            if filename.endswith('.py') and not filename.startswith('_')]
 __test__ = dict()
 
-for module in modules:
-    exec("from rest_framework.tests.%s import *" % module)
+if django.VERSION < (1, 6):
+    for module in modules:
+        exec("from rest_framework.tests.%s import *" % module)