Test case for issue #1609: PUT returns obsolete nested object.

rest_framework/tests/test_relations_nested.py

@@ -1,9 +1,11 @@
 from __future__ import unicode_literals
 from django.db import models
-from django.test import TestCase
+from django.test import TestCase, RequestFactory
 from rest_framework import serializers
+from rest_framework import generics
+import json
 
-from .models import OneToOneTarget
+from .models import OneToOneTarget, BlogPost, BlogPostComment
 
 
 class OneToOneSource(models.Model):
@@ -324,3 +326,90 @@ class ReverseNestedOneToManyTests(TestCase):
 
         ]
         self.assertEqual(serializer.data, expected)
+
+
+class NestedWritableSerializerUpdateTests(TestCase):
+
+    def test_post_nested_collection(self):
+        class BlogPostCommentSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = BlogPostComment
+                read_only_fields = ('id', 'blog_post')
+
+        class BlogPostSerializer(serializers.ModelSerializer):
+            comments = BlogPostCommentSerializer(
+                many=True, required=False,
+                allow_add_remove=True,
+                source='blogpostcomment_set',
+            )
+            class Meta:
+                model = BlogPost
+                fields = ('id', 'title', 'comments')
+
+        class BlogList(generics.RetrieveUpdateAPIView):
+            serializer_class = BlogPostSerializer
+
+            def get_queryset(self):
+                return BlogPost.objects.prefetch_related(
+                    'blogpostcomment_set',
+                ).all()
+
+        BlogPost.objects.create(pk=1, title="No text")
+
+        view = BlogList.as_view()
+        factory = RequestFactory()
+        request_data = {
+            "comments": [
+                {
+                    "id": None,
+                    "text": "First comment",
+                    "blog_post": None,
+                },
+                {
+                    "id": None,
+                    "text": "Second comment",
+                    "blog_post": None,
+                },
+            ],
+            "title": "Some text",
+        }
+        request_data = json.dumps(request_data)
+
+        request = factory.put(
+            '/blogs/1/', data=request_data, content_type='application/json',
+        )
+
+        response = view(request, pk=1)
+
+        expected_comments = BlogPostComment.objects.values().all()
+        self.assertEqual(len(expected_comments), 2)
+        self.assertTrue(all(x["blog_post_id"] == 1 for x in expected_comments))
+
+        response.render()
+        response_data = json.loads(response.content)
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response_data["id"], 1)
+        self.assertEqual(response_data["title"], "Some text")
+
+        response_comments = response_data["comments"]
+        self.assertEqual(len(response_comments), 2)
+
+        self.assertEqual(
+            response_comments[0]["id"],
+            expected_comments[0]["id"]
+        )
+
+        self.assertEqual(
+            response_comments[1]["id"],
+            expected_comments[1]["id"]
+        )
+
+        self.assertEqual(
+            response_comments[0]["blog_post"],
+            expected_comments[0]["blog_post_id"]
+        )
+        self.assertEqual(
+            response_comments[1]["blog_post"],
+            expected_comments[1]["blog_post_id"]
+        )
+