Merge pull request piccolo-orm#68 from piccolo-orm/test_inheritance

Test inheritance

Author: dantownsend

docs/src/piccolo/schema/advanced.rst

@@ -62,3 +62,24 @@ for example with ``table_finder`` (see :ref:`TableFinder`).
 
     class Band(Table, tags=["music"]):
         name = Varchar(length=100)
+
+-------------------------------------------------------------------------------
+
+Mixins
+------
+
+If you're frequently defining the same columns over and over again, you can
+use mixins to reduce the amount of repetition.
+
+.. code-block:: python
+
+    from piccolo.columns import Varchar, Boolean
+    from piccolo.table import Table
+
+
+    class FavouriteMixin:
+        favourite = Boolean(default=False)
+
+
+    class Manager(FavouriteMixin, Table):
+        name = Varchar()

tests/table/test_inheritance.py

@@ -0,0 +1,58 @@
+import datetime
+from unittest import TestCase
+
+from piccolo.columns import Varchar, Timestamp, Boolean
+from piccolo.table import Table
+
+
+class StartedOnMixin(Table):
+    """
+    A mixin which inherits from Table.
+    """
+
+    started_on = Timestamp()
+
+
+class FavouriteMixin:
+    """
+    A mixin which deliberately doesn't inherit from Table.
+    """
+
+    favourite = Boolean()
+
+
+class Manager(StartedOnMixin, FavouriteMixin, Table):
+    name = Varchar()
+
+
+class TestInheritance(TestCase):
+    """
+    Make sure columns can be inheritted from parent classes.
+    """
+
+    def setUp(self):
+        Manager.create_table().run_sync()
+
+    def tearDown(self):
+        Manager.alter().drop_table().run_sync()
+
+    def test_inheritance(self):
+        """
+        Test that a table created via inheritance works as expected.
+        """
+        # Make sure both columns can be retrieved:
+        for column_name in ("started_on", "name", "favourite"):
+            Manager._meta.get_column_by_name(column_name)
+
+        # Test saving and retrieving data:
+        started_on = datetime.datetime(year=1989, month=12, day=1)
+        name = "Guido"
+        favourite = True
+        Manager(
+            name=name, started_on=started_on, favourite=favourite
+        ).save().run_sync()
+
+        response = Manager.select().first().run_sync()
+        self.assertEqual(response["started_on"], started_on)
+        self.assertEqual(response["name"], name)
+        self.assertEqual(response["favourite"], favourite)