Quantize incoming digitals (#4339)

rest_framework/fields.py

@@ -955,7 +955,7 @@ class DecimalField(Field):
         if value in (decimal.Decimal('Inf'), decimal.Decimal('-Inf')):
             self.fail('invalid')
 
-        return self.validate_precision(value)
+        return self.quantize(self.validate_precision(value))
 
     def validate_precision(self, value):
         """
@@ -1018,7 +1018,8 @@ class DecimalField(Field):
         context.prec = self.max_digits
         return value.quantize(
             decimal.Decimal('.1') ** self.decimal_places,
-            context=context)
+            context=context
+        )
 
 
 # Date & time fields...

tests/test_fields.py

@@ -912,6 +912,26 @@ class TestLocalizedDecimalField(TestCase):
         self.assertTrue(isinstance(field.to_representation(Decimal('1.1')), six.string_types))
 
 
+class TestQuantizedValueForDecimal(TestCase):
+    def test_int_quantized_value_for_decimal(self):
+        field = serializers.DecimalField(max_digits=4, decimal_places=2)
+        value = field.to_internal_value(12).as_tuple()
+        expected_digit_tuple = (0, (1, 2, 0, 0), -2)
+        self.assertEqual(value, expected_digit_tuple)
+
+    def test_string_quantized_value_for_decimal(self):
+        field = serializers.DecimalField(max_digits=4, decimal_places=2)
+        value = field.to_internal_value('12').as_tuple()
+        expected_digit_tuple = (0, (1, 2, 0, 0), -2)
+        self.assertEqual(value, expected_digit_tuple)
+
+    def test_part_precision_string_quantized_value_for_decimal(self):
+        field = serializers.DecimalField(max_digits=4, decimal_places=2)
+        value = field.to_internal_value('12.0').as_tuple()
+        expected_digit_tuple = (0, (1, 2, 0, 0), -2)
+        self.assertEqual(value, expected_digit_tuple)
+
+
 class TestNoDecimalPlaces(FieldValues):
     valid_inputs = {
         '0.12345': Decimal('0.12345'),