Merge e2031c0e74 into 38a0e3e627

rest_framework/fields.py

@@ -1038,3 +1038,17 @@ class SerializerMethodField(Field):
     def field_to_native(self, obj, field_name):
         value = getattr(self.parent, self.method_name)(obj)
         return self.to_native(value)
+
+
+class SerializerLambdaField(Field):
+    """
+    A field that gets its value by calling a lambda.
+    """
+
+    def __init__(self, func, *args, **kwargs):
+        self.func = func
+        super(SerializerLambdaField, self).__init__(*args, **kwargs)
+
+    def field_to_native(self, obj, field_name):
+        value = self.func(obj)
+        return self.to_native(value)

rest_framework/tests/test_fields.py

@@ -1002,3 +1002,16 @@ class BooleanField(TestCase):
             bool_field = serializers.BooleanField(required=True)
 
         self.assertFalse(BooleanRequiredSerializer(data={}).is_valid())
+
+
+class SerializerLambdaFieldTest(TestCase):
+    """
+        Tests for the SerializerLambdaField field_to_native() behavior
+    """
+    class Example():
+        my_test = 'Hey, this is a test !'
+
+    def test_field_to_native(self):
+        s = serializers.SerializerLambdaField(lambda obj: obj.my_test)
+        result = s.field_to_native(self.Example(), None)
+        self.assertEqual(result, 'Hey, this is a test !')