more tests

rest_framework/fields.py

@@ -21,6 +21,7 @@ import collections
 import copy
 import datetime
 import decimal
+import importlib
 import inspect
 import re
 import uuid
@@ -1311,7 +1312,9 @@ class RecursiveField(Field):
     # __init__ on both the RecursiveField and the proxied field using the exact
     # same arguments.
 
-    def __init__(self, **kwargs):
+    def __init__(self, to='self', to_module=None, **kwargs):
+        self.to = to
+        self.to_module = to_module
         field_kwargs = dict(
             (key, kwargs[key])
             for key in kwargs
@@ -1323,9 +1326,17 @@ class RecursiveField(Field):
         super(RecursiveField, self).bind(field_name, parent)
 
         if hasattr(parent, 'child') and parent.child is self:
-            proxy_class = parent.parent.__class__
+            parent_class = parent.parent.__class__
         else:
-            proxy_class = parent.__class__
+            parent_class = parent.__class__
+
+        if self.to == 'self':
+            proxy_class = parent_class
+        else:
+            ref = importlib.import_module(self.to_module or parent_class.__module__)
+            for part in self.to.split('.'):
+                ref = getattr(ref, part)
+            proxy_class = ref 
 
         proxy = proxy_class(**self._kwargs)
         proxy.bind(field_name, parent)

tests/test_recursive.py

@@ -1,8 +1,7 @@
 from rest_framework import serializers
 
-
 class LinkSerializer(serializers.Serializer):
-    name = serializers.CharField()
+    name = serializers.CharField(max_length=25)
     next = serializers.RecursiveField(required=False, allow_null=True)
 
 
@@ -11,6 +10,26 @@ class NodeSerializer(serializers.Serializer):
     children = serializers.ListField(child=serializers.RecursiveField())
 
 
+class PingSerializer(serializers.Serializer):
+    ping_id = serializers.IntegerField()
+    pong = serializers.RecursiveField('PongSerializer', required=False)
+
+
+class PongSerializer(serializers.Serializer):
+    pong_id = serializers.IntegerField()
+    ping = PingSerializer()
+
+
+class SillySerializer(serializers.Serializer):
+    name = serializers.RecursiveField(
+        'CharField', 'rest_framework.fields', max_length=5)
+    blankable = serializers.RecursiveField(
+        'CharField', 'rest_framework.fields', allow_blank=True)
+    nullable = serializers.RecursiveField(
+        'CharField', 'rest_framework.fields', allow_null=True)
+    links = serializers.RecursiveField('LinkSerializer')
+    self = serializers.RecursiveField(required=False)
+
 class TestRecursiveField:
     @staticmethod
     def serialize(serializer_class, value):
@@ -57,3 +76,73 @@ class TestRecursiveField:
 
         self.serialize(NodeSerializer, value)
         self.deserialize(NodeSerializer, value)
+
+    def test_ping_pong(self):
+        pong = {
+            'pong_id': 4,
+            'ping': {
+                'ping_id': 3,
+                'pong': {
+                    'pong_id': 2,
+                    'ping': {
+                        'ping_id': 1,
+                    },
+                },
+            },
+        }
+        self.serialize(PongSerializer, pong)
+        self.deserialize(PongSerializer, pong)
+
+    def test_validation(self):
+        value = {
+            'name': 'good',
+            'blankable': '',
+            'nullable': None,
+            'links': {
+                'name': 'something',
+                'next': {
+                    'name': 'inner something',
+                }
+            }
+        }
+        self.serialize(SillySerializer, value)
+        self.deserialize(SillySerializer, value)
+
+        max_length = {
+            'name': 'too long',
+            'blankable': 'not blank',
+            'nullable': 'not null',
+            'links': {
+                'name': 'something',
+            }
+        }
+        serializer = SillySerializer(data=max_length)
+        assert not serializer.is_valid(), \
+            'validation should fail due to name too long'
+
+        nulled_out = {
+            'name': 'good',
+            'blankable': None,
+            'nullable': 'not null',
+            'links': {
+                'name': 'something',
+            }
+        }
+        serializer = SillySerializer(data=nulled_out)
+        assert not serializer.is_valid(), \
+            'validation should fail due to null field'
+
+        way_too_long = {
+            'name': 'good',
+            'blankable': '',
+            'nullable': None,
+            'links': {
+                'name': 'something',
+                'next': {
+                    'name': 'inner something that is much too long',
+                }
+            }
+        }
+        serializer = SillySerializer(data=way_too_long)
+        assert not serializer.is_valid(), \
+            'validation should fail on inner link validation'