Support format=None for date/time fields

2 files changed, 88 insertions, 9 deletions

diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index db7ceabb..cbd3334a 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -548,8 +548,8 @@ class DateField(Field):
     format = api_settings.DATE_FORMAT
     input_formats = api_settings.DATE_INPUT_FORMATS
 
-    def __init__(self, format=None, input_formats=None, *args, **kwargs):
-        self.format = format if format is not None else self.format
+    def __init__(self, format=empty, input_formats=None, *args, **kwargs):
+        self.format = format if format is not empty else self.format
         self.input_formats = input_formats if input_formats is not None else self.input_formats
         super(DateField, self).__init__(*args, **kwargs)
 
@@ -604,8 +604,8 @@ class DateTimeField(Field):
     input_formats = api_settings.DATETIME_INPUT_FORMATS
     default_timezone = timezone.get_default_timezone() if settings.USE_TZ else None
 
-    def __init__(self, format=None, input_formats=None, default_timezone=None, *args, **kwargs):
-        self.format = format if format is not None else self.format
+    def __init__(self, format=empty, input_formats=None, default_timezone=None, *args, **kwargs):
+        self.format = format if format is not empty else self.format
         self.input_formats = input_formats if input_formats is not None else self.input_formats
         self.default_timezone = default_timezone if default_timezone is not None else self.default_timezone
         super(DateTimeField, self).__init__(*args, **kwargs)
@@ -670,8 +670,8 @@ class TimeField(Field):
     format = api_settings.TIME_FORMAT
     input_formats = api_settings.TIME_INPUT_FORMATS
 
-    def __init__(self, format=None, input_formats=None, *args, **kwargs):
-        self.format = format if format is not None else self.format
+    def __init__(self, format=empty, input_formats=None, *args, **kwargs):
+        self.format = format if format is not empty else self.format
         self.input_formats = input_formats if input_formats is not None else self.input_formats
         super(TimeField, self).__init__(*args, **kwargs)
 
diff --git a/tests/test_fields.py b/tests/test_fields.py
index 0f445d41..b221089c 100644
--- a/tests/test_fields.py
+++ b/tests/test_fields.py
@@ -316,7 +316,9 @@ class TestDateField(FieldValues):
         '2001-99-99': ['Date has wrong format. Use one of these formats instead: YYYY[-MM[-DD]]'],
         datetime.datetime(2001, 1, 1, 12, 00): ['Expected a date but got a datetime.'],
     }
-    outputs = {}
+    outputs = {
+        datetime.date(2001, 1, 1): '2001-01-01',
+    }
     field = fields.DateField()
 
 
@@ -334,6 +336,30 @@ class TestCustomInputFormatDateField(FieldValues):
     field = fields.DateField(input_formats=['%d %b %Y'])
 
 
+class TestCustomOutputFormatDateField(FieldValues):
+    """
+    Values for `DateField` with a custom output format.
+    """
+    valid_inputs = {}
+    invalid_inputs = {}
+    outputs = {
+        datetime.date(2001, 1, 1): '01 Jan 2001'
+    }
+    field = fields.DateField(format='%d %b %Y')
+
+
+class TestNoOutputFormatDateField(FieldValues):
+    """
+    Values for `DateField` with no output format.
+    """
+    valid_inputs = {}
+    invalid_inputs = {}
+    outputs = {
+        datetime.date(2001, 1, 1): datetime.date(2001, 1, 1)
+    }
+    field = fields.DateField(format=None)
+
+
 class TestDateTimeField(FieldValues):
     """
     Valid and invalid values for `DateTimeField`.
@@ -351,7 +377,10 @@ class TestDateTimeField(FieldValues):
         '2001-99-99T99:00': ['Datetime has wrong format. Use one of these formats instead: YYYY-MM-DDThh:mm[:ss[.uuuuuu]][+HH:MM|-HH:MM|Z]'],
         datetime.date(2001, 1, 1): ['Expected a datetime but got a date.'],
     }
-    outputs = {}
+    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',
+    }
     field = fields.DateTimeField(default_timezone=timezone.UTC())
 
 
@@ -369,6 +398,30 @@ class TestCustomInputFormatDateTimeField(FieldValues):
     field = fields.DateTimeField(default_timezone=timezone.UTC(), input_formats=['%I:%M%p, %d %b %Y'])
 
 
+class TestCustomOutputFormatDateTimeField(FieldValues):
+    """
+    Values for `DateTimeField` with a custom output format.
+    """
+    valid_inputs = {}
+    invalid_inputs = {}
+    outputs = {
+        datetime.datetime(2001, 1, 1, 13, 00): '01:00PM, 01 Jan 2001',
+    }
+    field = fields.DateTimeField(format='%I:%M%p, %d %b %Y')
+
+
+class TestNoOutputFormatDateTimeField(FieldValues):
+    """
+    Values for `DateTimeField` with no output format.
+    """
+    valid_inputs = {}
+    invalid_inputs = {}
+    outputs = {
+        datetime.datetime(2001, 1, 1, 13, 00): datetime.datetime(2001, 1, 1, 13, 00),
+    }
+    field = fields.DateTimeField(format=None)
+
+
 class TestNaiveDateTimeField(FieldValues):
     """
     Valid and invalid values for `DateTimeField` with naive datetimes.
@@ -394,7 +447,9 @@ class TestTimeField(FieldValues):
         'abc': ['Time has wrong format. Use one of these formats instead: hh:mm[:ss[.uuuuuu]]'],
         '99:99': ['Time has wrong format. Use one of these formats instead: hh:mm[:ss[.uuuuuu]]'],
     }
-    outputs = {}
+    outputs = {
+        datetime.time(13, 00): '13:00:00'
+    }
     field = fields.TimeField()
 
 
@@ -412,6 +467,30 @@ class TestCustomInputFormatTimeField(FieldValues):
     field = fields.TimeField(input_formats=['%I:%M%p'])
 
 
+class TestCustomOutputFormatTimeField(FieldValues):
+    """
+    Values for `TimeField` with a custom output format.
+    """
+    valid_inputs = {}
+    invalid_inputs = {}
+    outputs = {
+        datetime.time(13, 00): '01:00PM'
+    }
+    field = fields.TimeField(format='%I:%M%p')
+
+
+class TestNoOutputFormatTimeField(FieldValues):
+    """
+    Values for `TimeField` with a no output format.
+    """
+    valid_inputs = {}
+    invalid_inputs = {}
+    outputs = {
+        datetime.time(13, 00): datetime.time(13, 00)
+    }
+    field = fields.TimeField(format=None)
+
+
 # Choice types...
 
 class TestChoiceField(FieldValues):