add Decimal field (#104)

Author: aminalaee

.github/workflows/test-suite.yml

@@ -16,6 +16,17 @@ jobs:
       matrix:
         python-version: ["3.6", "3.7", "3.8", "3.9", "3.10.0-rc.1"]
 
+    services:
+      postgres:
+        image: postgres:10.8
+        env:
+          POSTGRES_USER: username
+          POSTGRES_PASSWORD: password
+          POSTGRES_DB: testsuite
+        ports:
+          - 5432:5432
+        options: --health-cmd pg_isready --health-interval 10s --health-timeout 5s --health-retries 5
+
     steps:
       - uses: "actions/checkout@v2"
       - uses: "actions/setup-python@v2"
@@ -28,6 +39,8 @@ jobs:
       - name: "Build package & docs"
         run: "scripts/build"
       - name: "Run tests"
+        env:
+          TEST_DATABASE_URL: "postgresql://username:password@localhost:5432/testsuite"
         run: "scripts/test"
       - name: "Enforce coverage"
         run: "scripts/coverage"

docs/declaring_models.md

@@ -62,6 +62,7 @@ See `TypeSystem` for [type-specific validation keyword arguments][typesystem-fie
 * `orm.Boolean()`
 * `orm.Date()`
 * `orm.DateTime()`
+* `orm.Decimal()`
 * `orm.Enum()`
 * `orm.Float()`
 * `orm.Integer()`

orm/__init__.py

@@ -5,6 +5,7 @@
     Boolean,
     Date,
     DateTime,
+    Decimal,
     Enum,
     Float,
     ForeignKey,
@@ -15,14 +16,15 @@
 )
 from orm.models import Model
 
-__version__ = "0.1.7"
+__version__ = "0.1.8"
 __all__ = [
     "NoMatch",
     "MultipleMatches",
     "BigInteger",
     "Boolean",
     "Date",
     "DateTime",
+    "Decimal",
     "Enum",
     "Float",
     "Integer",

orm/fields.py

@@ -126,3 +126,15 @@ def __init__(self, enum, **kwargs):
 
     def get_column_type(self):
         return sqlalchemy.Enum(self.enum)
+
+
+class Decimal(ModelField, typesystem.Decimal):
+    def __init__(self, max_digits: int, decimal_places: int, **kwargs):
+        assert max_digits, "max_digits is required"
+        assert decimal_places, "decimal_places is required"
+        self.max_digits = max_digits
+        self.decimal_places = decimal_places
+        super().__init__(**kwargs)
+
+    def get_column_type(self):
+        return sqlalchemy.Numeric(precision=self.max_digits, scale=self.decimal_places)

orm/models.py

@@ -365,7 +365,7 @@ async def load(self):
         row = await self.__database__.fetch_one(expr)
 
         # Update the instance.
-        for key, value in dict(row).items():
+        for key, value in dict(row._mapping).items():
             setattr(self, key, value)
 
     @classmethod

requirements.txt

@@ -1,4 +1,5 @@
-databases[sqlite]
+databases[postgresql]
+psycopg2
 typesystem
 
 # Packaging

tests/settings.py

@@ -1,3 +1,5 @@
 import os
 
-DATABASE_URL = os.getenv("DATABASE_URL", "sqlite:///test.db")
+assert "TEST_DATABASE_URL" in os.environ, "TEST_DATABASE_URL is not set."
+
+DATABASE_URL = os.environ["TEST_DATABASE_URL"]

tests/test_columns.py

@@ -1,4 +1,5 @@
 import datetime
+import decimal
 from enum import Enum
 
 import databases
@@ -35,6 +36,7 @@ class Example(orm.Model):
     created_time = orm.Time(default=time)
     description = orm.Text(allow_blank=True)
     value = orm.Float(allow_null=True)
+    price = orm.Decimal(max_digits=5, decimal_places=2, allow_null=True)
     data = orm.JSON(default={})
     status = orm.Enum(StatusEnum, default=StatusEnum.DRAFT)
 
@@ -57,13 +59,18 @@ async def test_model_crud():
         assert example.created_day == datetime.date.today()
         assert example.description == ""
         assert example.value is None
+        assert example.price is None
         assert example.data == {}
         assert example.status == StatusEnum.DRAFT
 
         await example.update(
-            data={"foo": 123}, value=123.456, status=StatusEnum.RELEASED
+            data={"foo": 123},
+            value=123.456,
+            status=StatusEnum.RELEASED,
+            price=decimal.Decimal("999.99"),
         )
         example = await Example.objects.get()
         assert example.value == 123.456
         assert example.data == {"foo": 123}
         assert example.status == StatusEnum.RELEASED
+        assert example.price == decimal.Decimal("999.99")

tests/test_models.py

@@ -172,23 +172,19 @@ async def test_model_order_by():
 
         users = await User.objects.order_by("name", "-id").all()
         assert users[0].name == "Allen"
-        assert users[0].id == 2
         assert users[1].name == "Bob"
-        assert users[1].id == 3
+        assert users[0].id < users[1].id
 
         users = await User.objects.filter(name="Bob").order_by("-id").all()
         assert users[0].name == "Bob"
-        assert users[0].id == 3
         assert users[1].name == "Bob"
-        assert users[1].id == 1
+        assert users[0].id > users[1].id
 
         users = await User.objects.order_by("id").limit(1).all()
         assert users[0].name == "Bob"
-        assert users[0].id == 1
 
         users = await User.objects.order_by("id").limit(1).offset(1).all()
         assert users[0].name == "Allen"
-        assert users[0].id == 2
 
 
 async def test_model_exists():