Merge pull request #3731 from mjparker777/master

Issue 3726 DateTimeField not handling empty values

rest_framework/fields.py

@@ -1061,6 +1061,9 @@ class DateTimeField(Field):
         self.fail('invalid', format=humanized_format)
 
     def to_representation(self, value):
+        if not value:
+            return None
+
         output_format = getattr(self, 'format', api_settings.DATETIME_FORMAT)
 
         if output_format is None:
@@ -1118,11 +1121,11 @@ class DateField(Field):
         self.fail('invalid', format=humanized_format)
 
     def to_representation(self, value):
-        output_format = getattr(self, 'format', api_settings.DATE_FORMAT)
-
         if not value:
             return None
 
+        output_format = getattr(self, 'format', api_settings.DATE_FORMAT)
+
         if output_format is None:
             return value
 
@@ -1183,6 +1186,9 @@ class TimeField(Field):
         self.fail('invalid', format=humanized_format)
 
     def to_representation(self, value):
+        if not value:
+            return None
+
         output_format = getattr(self, 'format', api_settings.TIME_FORMAT)
 
         if output_format is None:

tests/test_fields.py

@@ -959,7 +959,9 @@ class TestDateTimeField(FieldValues):
     }
     outputs = {
         datetime.datetime(2001, 1, 1, 13, 00): '2001-01-01T13:00:00',
-        datetime.datetime(2001, 1, 1, 13, 00, tzinfo=timezone.UTC()): '2001-01-01T13:00:00Z'
+        datetime.datetime(2001, 1, 1, 13, 00, tzinfo=timezone.UTC()): '2001-01-01T13:00:00Z',
+        None: None,
+        '': None,
     }
     field = serializers.DateTimeField(default_timezone=timezone.UTC())
 
@@ -1028,7 +1030,9 @@ class TestTimeField(FieldValues):
         '99:99': ['Time has wrong format. Use one of these formats instead: hh:mm[:ss[.uuuuuu]].'],
     }
     outputs = {
-        datetime.time(13, 00): '13:00:00'
+        datetime.time(13, 00): '13:00:00',
+        None: None,
+        '': None,
     }
     field = serializers.TimeField()