change quantity to DecimalType

openregistry/api/models/ocds.py

@@ -2,11 +2,14 @@
 from uuid import uuid4
 
 from schematics.types import (StringType, FloatType, URLType, IntType,
-                              BooleanType, BaseType, EmailType, MD5Type)
-from schematics.exceptions import ValidationError
+                              BooleanType, BaseType, EmailType, MD5Type,
+                              DecimalType as BaseDecimalType)
+from schematics.exceptions import ValidationError, ConversionError
 from schematics.types.compound import ModelType, ListType
 from schematics.types.serializable import serializable
 
+from decimal import Decimal, InvalidOperation, ROUND_HALF_UP
+
 from openregistry.api.constants import (DEFAULT_CURRENCY,
     DEFAULT_ITEM_CLASSIFICATION, ITEM_CLASSIFICATIONS, DOCUMENT_TYPES,
     IDENTIFIER_CODES, DEBTOR_TYPES
@@ -147,6 +150,29 @@ class Identifier(Model):
     uri = URLType()  # A URI to identify the organization.
 
 
+class DecimalType(BaseDecimalType):
+
+    def __init__(self, precision=-3, **kwargs):
+        self.precision = Decimal("1E{:d}".format(precision))
+        super(DecimalType, self).__init__(**kwargs)
+
+    def to_primitive(self, value, context=None):
+        return value
+
+    def to_native(self, value, context=None):
+        try:
+            value = Decimal(value).quantize(self.precision, rounding=ROUND_HALF_UP).normalize()
+        except (TypeError, InvalidOperation):
+            raise ConversionError(self.messages['number_coerce'].format(value))
+
+        if self.min_value is not None and value < self.min_value:
+            raise ConversionError(self.messages['number_min'].format(value))
+        if self.max_value is not None and self.max_value < value:
+            raise ConversionError(self.messages['number_max'].format(value))
+
+        return value
+
+
 class Item(Model):
     """A good, service, or work to be contracted."""
     id = StringType(required=True, min_length=1, default=lambda: uuid4().hex)
@@ -156,7 +182,7 @@ class Item(Model):
     classification = ModelType(ItemClassification)
     additionalClassifications = ListType(ModelType(Classification), default=list())
     unit = ModelType(Unit)  # Description of the unit which the good comes in e.g. hours, kilograms
-    quantity = IntType()  # The number of units required
+    quantity = DecimalType()  # The number of units required
     address = ModelType(Address)
     location = ModelType(Location)
 

openregistry/api/tests/models.py

@@ -3,6 +3,7 @@
 import mock
 from datetime import datetime, timedelta
 from schematics.exceptions import ConversionError, ValidationError, ModelValidationError
+from decimal import Decimal
 
 from openregistry.api.utils import get_now
 
@@ -12,7 +13,7 @@
 from openregistry.api.models.ocds import (
     Organization, ContactPoint, Identifier, Address,
     Item, Location, Unit, Value, ItemClassification, Classification,
-    Period, PeriodEndRequired, Document
+    Period, PeriodEndRequired, Document, DecimalType
 )
 
 
@@ -45,6 +46,28 @@ def test_IsoDateTimeType_model(self):
             with self.assertRaises(ConversionError):
                 dt.to_native(dt.to_primitive(date))
 
+    def test_DecimalType_model(self):
+        number = '5.001'
+
+        dt = DecimalType()
+
+        value = dt.to_primitive(number)
+        self.assertEqual(Decimal(number), dt.to_native(number))
+        self.assertEqual(Decimal(number), dt.to_native(value))
+
+        for number in (None, '5,5'):
+            with self.assertRaisesRegexp(ConversionError, u"Number '{}' failed to convert to a decimal.".format(number)):
+                dt.to_native(number)
+
+        dt = DecimalType(precision=-3, min_value=Decimal('0'), max_value=Decimal('10.0'))
+
+        self.assertEqual(Decimal('0.111'), dt.to_native('0.11111'))
+        self.assertEqual(Decimal('0.556'), dt.to_native('0.55555'))
+
+        for number in ('-1.0', '11.0'):
+            with self.assertRaises(ConversionError):
+                dt.to_native(dt.to_primitive(number))
+
     def test_HashType_model(self):
         from uuid import uuid4
 
@@ -263,7 +286,7 @@ def test_Item_model(self):
                 "name": u"item",
                 "code": u"39513200-3"
             },
-            "quantity": 5,
+            "quantity": Decimal('5.001'),
             "address": {
                 "countryName": u"Україна",
                 "postalCode": "79000",