[1.9.x] Separated natural key serialization tests

Backport of d59d3caf3 from master.

tests/serializers/test_natural.py

@@ -0,0 +1,70 @@
+from __future__ import unicode_literals
+
+from django.core import serializers
+from django.db import connection
+from django.test import TestCase
+
+from .models import FKDataNaturalKey, NaturalKeyAnchor
+from .tests import register_tests
+
+
+class NaturalKeySerializerTests(TestCase):
+    pass
+
+
+def natural_key_serializer_test(format, self):
+    # Create all the objects defined in the test data
+    with connection.constraint_checks_disabled():
+        objects = [
+            NaturalKeyAnchor.objects.create(id=1100, data="Natural Key Anghor"),
+            FKDataNaturalKey.objects.create(id=1101, data_id=1100),
+            FKDataNaturalKey.objects.create(id=1102, data_id=None),
+        ]
+    # Serialize the test database
+    serialized_data = serializers.serialize(format, objects, indent=2,
+        use_natural_foreign_keys=True)
+
+    for obj in serializers.deserialize(format, serialized_data):
+        obj.save()
+
+    # Assert that the deserialized data is the same
+    # as the original source
+    for obj in objects:
+        instance = obj.__class__.objects.get(id=obj.pk)
+        self.assertEqual(obj.data, instance.data,
+             "Objects with PK=%d not equal; expected '%s' (%s), got '%s' (%s)" % (
+                 obj.pk, obj.data, type(obj.data), instance, type(instance.data))
+        )
+
+
+def natural_key_test(format, self):
+    book1 = {'data': '978-1590597255', 'title': 'The Definitive Guide to '
+             'Django: Web Development Done Right'}
+    book2 = {'data': '978-1590599969', 'title': 'Practical Django Projects'}
+
+    # Create the books.
+    adrian = NaturalKeyAnchor.objects.create(**book1)
+    james = NaturalKeyAnchor.objects.create(**book2)
+
+    # Serialize the books.
+    string_data = serializers.serialize(format, NaturalKeyAnchor.objects.all(),
+                                        indent=2, use_natural_foreign_keys=True,
+                                        use_natural_primary_keys=True)
+
+    # Delete one book (to prove that the natural key generation will only
+    # restore the primary keys of books found in the database via the
+    # get_natural_key manager method).
+    james.delete()
+
+    # Deserialize and test.
+    books = list(serializers.deserialize(format, string_data))
+    self.assertEqual(len(books), 2)
+    self.assertEqual(books[0].object.title, book1['title'])
+    self.assertEqual(books[0].object.pk, adrian.pk)
+    self.assertEqual(books[1].object.title, book2['title'])
+    self.assertEqual(books[1].object.pk, None)
+
+
+# Dynamically register tests for each serializer
+register_tests(NaturalKeySerializerTests, 'test_%s_natural_key_serializer', natural_key_serializer_test)
+register_tests(NaturalKeySerializerTests, 'test_%s_serializer_natural_keys', natural_key_test)