'Tests that column attributes are moved to a _columns dict
and replaced with simple value attributes'

def test_column_attributes_handled_correctly(self):

    class TestModel(Model, ):
        id = columns.UUID(primary_key=True, default=(lambda : uuid4()))
        text = columns.Text()
    self.assertHasAttr(TestModel, '_columns')
    self.assertHasAttr(TestModel, 'id')
    self.assertHasAttr(TestModel, 'text')
    inst = TestModel()
    self.assertHasAttr(inst, 'id')
    self.assertHasAttr(inst, 'text')
    self.assertIsNotNone(inst.id)
    self.assertIsNone(inst.text)
