min_value/max_value support in DurationField (#5643)

* Added min_value/max_value field arguments to DurationField.
* Made field mapping use mix/max kwargs for DurationField validators.

Author: noamkush

docs/api-guide/fields.md

@@ -360,7 +360,10 @@ Corresponds to `django.db.models.fields.DurationField`
 The `validated_data` for these fields will contain a `datetime.timedelta` instance.
 The representation is a string following this format `'[DD] [HH:[MM:]]ss[.uuuuuu]'`.
 
-**Signature:** `DurationField()`
+**Signature:** `DurationField(max_value=None, min_value=None)`
+
+- `max_value` Validate that the duration provided is no greater than this value.
+- `min_value` Validate that the duration provided is no less than this value.
 
 ---
 

rest_framework/fields.py

@@ -1354,8 +1354,27 @@ def to_representation(self, value):
 class DurationField(Field):
     default_error_messages = {
         'invalid': _('Duration has wrong format. Use one of these formats instead: {format}.'),
+        'max_value': _('Ensure this value is less than or equal to {max_value}.'),
+        'min_value': _('Ensure this value is greater than or equal to {min_value}.'),
     }
 
+    def __init__(self, **kwargs):
+        self.max_value = kwargs.pop('max_value', None)
+        self.min_value = kwargs.pop('min_value', None)
+        super(DurationField, self).__init__(**kwargs)
+        if self.max_value is not None:
+            message = lazy(
+                self.error_messages['max_value'].format,
+                six.text_type)(max_value=self.max_value)
+            self.validators.append(
+                MaxValueValidator(self.max_value, message=message))
+        if self.min_value is not None:
+            message = lazy(
+                self.error_messages['min_value'].format,
+                six.text_type)(min_value=self.min_value)
+            self.validators.append(
+                MinValueValidator(self.min_value, message=message))
+
     def to_internal_value(self, value):
         if isinstance(value, datetime.timedelta):
             return value

rest_framework/utils/field_mapping.py

@@ -12,7 +12,7 @@
 from rest_framework.validators import UniqueValidator
 
 NUMERIC_FIELD_TYPES = (
-    models.IntegerField, models.FloatField, models.DecimalField
+    models.IntegerField, models.FloatField, models.DecimalField, models.DurationField,
 )
 
 

tests/test_fields.py

@@ -1459,6 +1459,23 @@ class TestNoOutputFormatTimeField(FieldValues):
     field = serializers.TimeField(format=None)
 
 
+class TestMinMaxDurationField(FieldValues):
+    """
+    Valid and invalid values for `DurationField` with min and max limits.
+    """
+    valid_inputs = {
+        '3 08:32:01.000123': datetime.timedelta(days=3, hours=8, minutes=32, seconds=1, microseconds=123),
+        86401: datetime.timedelta(days=1, seconds=1),
+    }
+    invalid_inputs = {
+        3600: ['Ensure this value is greater than or equal to 1 day, 0:00:00.'],
+        '4 08:32:01.000123': ['Ensure this value is less than or equal to 4 days, 0:00:00.'],
+        '3600': ['Ensure this value is greater than or equal to 1 day, 0:00:00.'],
+    }
+    outputs = {}
+    field = serializers.DurationField(min_value=datetime.timedelta(days=1), max_value=datetime.timedelta(days=4))
+
+
 class TestDurationField(FieldValues):
     """
     Valid and invalid values for `DurationField`.

tests/test_model_serializer.py

@@ -7,6 +7,7 @@
 """
 from __future__ import unicode_literals
 
+import datetime
 import decimal
 from collections import OrderedDict
 
@@ -16,7 +17,6 @@
     MaxValueValidator, MinLengthValidator, MinValueValidator
 )
 from django.db import models
-from django.db.models import DurationField as ModelDurationField
 from django.test import TestCase
 from django.utils import six
 
@@ -349,7 +349,7 @@ class DurationFieldModel(models.Model):
             """
             A model that defines DurationField.
             """
-            duration_field = ModelDurationField()
+            duration_field = models.DurationField()
 
         class TestSerializer(serializers.ModelSerializer):
             class Meta:
@@ -363,6 +363,27 @@ class Meta:
         """)
         self.assertEqual(unicode_repr(TestSerializer()), expected)
 
+    def test_duration_field_with_validators(self):
+        class ValidatedDurationFieldModel(models.Model):
+            """
+            A model that defines DurationField with validators.
+            """
+            duration_field = models.DurationField(
+                validators=[MinValueValidator(datetime.timedelta(days=1)), MaxValueValidator(datetime.timedelta(days=3))]
+            )
+
+        class TestSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = ValidatedDurationFieldModel
+                fields = '__all__'
+
+        expected = dedent("""
+            TestSerializer():
+                id = IntegerField(label='ID', read_only=True)
+                duration_field = DurationField(max_value=datetime.timedelta(3), min_value=datetime.timedelta(1))
+        """)
+        self.assertEqual(unicode_repr(TestSerializer()), expected)
+
 
 class TestGenericIPAddressFieldValidation(TestCase):
     def test_ip_address_validation(self):