Fix pk relations tests which were not running.

rest_framework/tests/relations_pk.py

@@ -2,6 +2,7 @@ from __future__ import unicode_literals
 from django.test import TestCase
 from rest_framework import serializers
 from rest_framework.tests.models import ManyToManyTarget, ManyToManySource, ForeignKeyTarget, ForeignKeySource, NullableForeignKeySource, OneToOneTarget, NullableOneToOneSource
+from rest_framework.compat import six
 
 
 class ManyToManyTargetSerializer(serializers.ModelSerializer):
@@ -200,7 +201,7 @@ class PKForeignKeyTests(TestCase):
         instance = ForeignKeySource.objects.get(pk=1)
         serializer = ForeignKeySourceSerializer(instance, data=data)
         self.assertFalse(serializer.is_valid())
-        self.assertEquals(serializer.errors, {'target': ['Incorrect type.  Expected pk value, received str.']})
+        self.assertEquals(serializer.errors, {'target': ['Incorrect type.  Expected pk value, received %s.' % six.text_type.__name__]})
 
     def test_reverse_foreign_key_update(self):
         data = {'id': 2, 'name': 'target-2', 'sources': [1, 3]}
@@ -271,7 +272,7 @@ class PKForeignKeyTests(TestCase):
         instance = ForeignKeySource.objects.get(pk=1)
         serializer = ForeignKeySourceSerializer(instance, data=data)
         self.assertFalse(serializer.is_valid())
-        self.assertEquals(serializer.errors, {'target': ['Value may not be null']})
+        self.assertEquals(serializer.errors, {'target': ['This field is required.']})
 
 
 class PKNullableForeignKeyTests(TestCase):

rest_framework/tests/relations_slug.py

@@ -25,7 +25,7 @@ class NullableForeignKeySourceSerializer(serializers.ModelSerializer):
 
 
 # TODO: M2M Tests, FKTests (Non-nulable), One2One
-class PKForeignKeyTests(TestCase):
+class SlugForeignKeyTests(TestCase):
     def setUp(self):
         target = ForeignKeyTarget(name='target-1')
         target.save()