unit test for required false nested serializers

tests/test_serializer_nested.py

@@ -38,3 +38,70 @@ class TestNestedSerializer:
         }
         serializer = self.Serializer()
         assert serializer.data == expected_data
+
+
+class TestRequiredFalseNestedSerializer:
+    def setup(self):
+        class NestedSerializer(serializers.Serializer):
+            one = serializers.IntegerField(max_value=10)
+
+        class TestSerializer(serializers.Serializer):
+            nested = NestedSerializer(required=False)
+
+        self.Serializer = TestSerializer
+
+        class FakeMultiDict(dict):
+            """
+            Use this to fake a `format="multipart"` request, because
+            `utils.is_html_input()` returns `True` when the dict object has
+            an attribute of "getlist".
+            """
+            def getlist(self, value, default=None):
+                if value in self:
+                    return [self[value]]
+                else:
+                    return [] if default is None else default
+
+        self.FakeMultiDict = FakeMultiDict
+
+    def test_nested_json_validate(self):
+        input_data = {
+            'nested': {
+                'one': '1',
+            },
+        }
+        expected_data = {
+            'nested': {
+                'one': 1,
+            },
+        }
+        serializer = self.Serializer(data=input_data)
+        assert serializer.is_valid()
+        assert serializer.validated_data == expected_data
+
+    def test_missing_nested_json_validate(self):
+        input_data = {}
+        expected_data = {}
+        serializer = self.Serializer(data=input_data)
+        assert serializer.is_valid()
+        assert serializer.validated_data == expected_data
+
+    def test_nested_multipart_validate(self):
+        input_data = self.FakeMultiDict(**{
+            'nested.one': '1',
+        })
+        expected_data = {
+            'nested': {
+                'one': 1,
+            },
+        }
+        serializer = self.Serializer(data=input_data)
+        assert serializer.is_valid()
+        assert serializer.validated_data == expected_data
+
+    def test_missing_nested_multipart_validate(self):
+        input_data = self.FakeMultiDict()
+        expected_data = {}
+        serializer = self.Serializer(data=input_data)
+        assert serializer.is_valid()
+        assert serializer.validated_data == expected_data