Models are specializations of themselves

djeneralize/models.py

@@ -80,8 +80,8 @@ def __new__(cls, name, bases, attrs):
             # This must be a direct descendant from the BaseGeneralizationModel.
             # Prepare the look-up mapping of specializations which the sub-
             # classes will update:
-            new_model._meta.specializations = {}
             new_model._meta.specialization = PATH_SEPERATOR
+            new_model._meta.specializations = {new_model._meta.specialization: new_model}
 
             if specialization is not None:
                 # We need to ensure this is actually None and not just evaluates
@@ -103,7 +103,6 @@ def __new__(cls, name, bases, attrs):
 
             parent_class = new_model.__base__
 
-            new_model._meta.specializations = {}
             new_model._generalized_parent = parent_class
 
             path_specialization = '%s%s%s' % (
@@ -114,7 +113,8 @@ def __new__(cls, name, bases, attrs):
             # Calculate the specialization as a path taking into account the
             # specialization of any ancestors:
             new_model._meta.specialization = path_specialization
-
+            new_model._meta.specializations = {new_model._meta.specialization: new_model}
+
             # Update the specializations mapping on the General model so that it
             # knows to use this class for that specialization:
             ancestor = getattr(new_model, '_generalized_parent', None)
@@ -187,14 +187,12 @@ def __init__(self, *args, **kwargs):
         declared in Meta
 
         """
-
-        super(BaseGeneralizationModel, self).__init__(*args, **kwargs)
-
         # If we have a final specialization, and a specialization_type is not
         # specified in kwargs, set it to the default for this model:
-        if ('specialization_type' not in kwargs and
-            not self._meta.specializations):
-            self.specialization_type = self.__class__.model_specialization
+        if ('specialization_type' not in kwargs):
+            kwargs['specialization_type'] = self.__class__.model_specialization
+
+        super(BaseGeneralizationModel, self).__init__(*args, **kwargs)
 
     class Meta:
         abstract = True
@@ -212,13 +210,13 @@ def get_as_specialization(self, final_specialization=True):
 
         """
 
-        path = self.specialization_type
-
-        if not final_specialization:
+        current_path = self.__class__.model_specialization
+        path = self.specialization_type        
+
+        if not final_specialization and not path is current_path:
             # We need to find the path which is only one-step down from the
             # current level of specialization.
-            path = find_next_path_down(self.__class__.model_specialization,
-                                       path, PATH_SEPERATOR)
+            path = find_next_path_down(current_path, path, PATH_SEPERATOR)
 
         return self._meta.specializations[path].objects.get(pk=self.pk)
 
@@ -280,4 +278,4 @@ def ensure_specialization_manager(sender, **kwargs):
                 )
 
 specialized_model_prepared.connect(ensure_specialization_manager)
-#}
+#}

tests/fixtures.py → tests/test_djeneralize/fixtures.py

@@ -12,8 +12,8 @@
 # INFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE.
 #
 ##############################################################################
-from tests.test_djeneralize.producers.models import EcoProducer
-from tests.test_djeneralize.fruit.models import Banana
+from test_djeneralize.producers.models import EcoProducer
+from test_djeneralize.fruit.models import Banana
 
 """Fixtures for djeneralize tests"""
 
@@ -129,4 +129,4 @@ class Meta:
     class EcoMart:
         name = 'EcoMart'
         producer = EcoProducerData.BananaProducer
-
+

tests/test_djeneralize/settings.py

@@ -15,6 +15,9 @@
 ##############################################################################
 
 from os import path
+# add djeneralize to the path
+import sys
+sys.path.append('../..')
 
 def get_and_ensure_exists_path_to_db_file():
     """
@@ -31,6 +34,8 @@ def get_and_ensure_exists_path_to_db_file():
     return db_path
 
 
+TEST_RUNNER = 'django_nose.NoseTestSuiteRunner'
+
 # Django settings for test_djeneralize project.
 
 DEBUG = True
@@ -122,7 +127,8 @@ def get_and_ensure_exists_path_to_db_file():
     'django.contrib.sessions',
     'django.contrib.sites',
     'django.contrib.messages',
-    'tests.test_djeneralize.writing',
-    'tests.test_djeneralize.fruit',
-    'tests.test_djeneralize.producers',
+    'test_djeneralize.writing',
+    'test_djeneralize.fruit',
+    'test_djeneralize.producers',
+    'django_nose',
 )

tests/test_base.py → tests/test_djeneralize/tests/test_base.py

@@ -15,9 +15,6 @@
 ##############################################################################
 
 from itertools import chain
-import os
-# Ensure that Django knows where the project is:
-os.environ['DJANGO_SETTINGS_MODULE'] = 'tests.test_djeneralize.settings'
 
 from django.http import Http404
 from fixture.django_testcase import FixtureTestCase
@@ -26,8 +23,8 @@
     )
 
 from djeneralize.utils import *
-from .fixtures import *
-from .test_djeneralize.writing.models import *
+from test_djeneralize.fixtures import *
+from test_djeneralize.writing.models import *
 
 
 class TestMetaclass(object):
@@ -37,19 +34,21 @@ class TestMetaclass(object):
     def test_specializations_general(self):
         """
         The specializations dictionary on the most general case is populated
-        with all the descdencts direct or otherwise.
+        with all the descdencts direct or otherwise or the model itself.
 
         """
 
         specializations = WritingImplement._meta.specializations
         specializations_classes = set(specializations.values())
         specializations_keys = set(specializations.keys())
 
+        ok_(WritingImplement in specializations_classes)
         ok_(Pen in specializations_classes)
         ok_(Pencil in specializations_classes)
         ok_(FountainPen in specializations_classes)
         ok_(BallPointPen in specializations_classes)
 
+        ok_(WritingImplement.model_specialization in specializations_keys)
         ok_(Pen.model_specialization in specializations_keys)
         ok_(Pencil.model_specialization in specializations_keys)
         ok_(FountainPen.model_specialization in specializations_keys)
@@ -58,26 +57,26 @@ def test_specializations_general(self):
 
     def test_sub_specialization(self):
         """
-        Only the child specializations are stored in a specialization of the
-        general case.
+        Only the child specializations and the model iself are stored in a specialization of the
+        most general case.
 
         """
 
         specializations = Pen._meta.specializations
         specializations_classes = set(specializations.values())
         specializations_keys = set(specializations.keys())
 
-        assert_false(Pen in specializations_classes)
         assert_false(Pencil in specializations_classes)
+        ok_(Pen in specializations_classes)
         ok_(FountainPen in specializations_classes)
         ok_(BallPointPen in specializations_classes)
 
-        assert_false(Pen.model_specialization in specializations_keys)
         assert_false(Pencil.model_specialization in specializations_keys)
+        ok_(Pen.model_specialization in specializations_keys)
         ok_(FountainPen.model_specialization in specializations_keys)
         ok_(BallPointPen.model_specialization in specializations_keys)
 
-        eq_(BallPointPen._meta.specializations, {})
+        eq_(BallPointPen._meta.specializations, {BallPointPen.model_specialization: BallPointPen})
 
     def test_path_specialization(self):
         """
@@ -162,17 +161,6 @@ class TestModelInstance(FixtureTestCase):
     """Tests for model instances"""
 
     datasets = [PenData, PencilData, FountainPenData, BallPointPenData]
-
-    def test_no_matching_specialization_raises_key_error(self):
-        """
-        If get_as_specialization is called on the most specialized instance a
-        key error will be raised.
-
-        """
-
-        pencil = Pencil.objects.all()[0]
-
-        assert_raises(KeyError, pencil.get_as_specialization)
 
     def test_final_specialization(self):
         """
@@ -186,8 +174,8 @@ def test_final_specialization(self):
         montblanc_special = FountainPen.objects.get(name='Mont Blanc')
 
         eq_(montblanc_general.get_as_specialization(), montblanc_special)
-
         eq_(montblanc_intermediate.get_as_specialization(), montblanc_special)
+        eq_(montblanc_special.get_as_specialization(), montblanc_special)
 
     def test_direct_specialization(self):
         """
@@ -275,6 +263,36 @@ def test_all_final(self):
                 model_value = getattr(wi, field_name)
                 eq_(model_value, value)
 
+
+    def test_all_final_on_model_with_instances(self):
+        """
+        The all() method on the manager and queryset returns final 
+        specializations, on a model that has instances of itself AND specialized instances.
+
+        """
+        all_pens = Pen.specializations.all()
+
+        models = set(m.__class__ for m in all_pens)
+
+        assert_false(WritingImplement in models)
+        ok_(Pen in models)
+        ok_(FountainPen in models)
+        ok_(BallPointPen in models)
+
+
+        # Ensure that all the objects have the correct fields and values
+        # specified in their original definition, i.e. they've been
+        # reconstituted correctly:
+        for p in all_pens:
+            dataset = self.datasets[p.name]
+
+            for field_name, value in dataset.__dict__.items():
+                if field_name.startswith('_') or field_name == 'ref':
+                    continue
+
+                model_value = getattr(p, field_name)
+                eq_(model_value, value)
+
     def test_all_direct(self):
         """
         The all() method on the manager and queryset returns direct 

tests/test_fields.py → tests/test_djeneralize/tests/test_fields.py

@@ -12,17 +12,14 @@
 # INFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE.
 #
 ##############################################################################
-import os
-# Ensure that Django knows where the project is:
-os.environ['DJANGO_SETTINGS_MODULE'] = 'tests.test_djeneralize.settings'
 
 from fixture.django_testcase import FixtureTestCase
 from nose.tools import eq_
 
-from tests.fixtures import BananaData, EcoProducerData, PenData, ShopData
-from tests.test_djeneralize.fruit.models import Banana
-from tests.test_djeneralize.producers.models import EcoProducer, Shop
-from tests.test_djeneralize.writing.models import WritingImplement
+from test_djeneralize.fixtures import BananaData, EcoProducerData, PenData, ShopData
+from test_djeneralize.fruit.models import Banana
+from test_djeneralize.producers.models import EcoProducer, Shop
+from test_djeneralize.writing.models import WritingImplement
 
 
 class TestForeignKey(FixtureTestCase):

tests/test_integration.py → tests/test_djeneralize/tests/test_integration.py

@@ -16,10 +16,6 @@
 
 """Integration tests to confirm nothing Django-related is broken"""
 
-import os
-# Ensure that Django knows where the project is:
-os.environ['DJANGO_SETTINGS_MODULE'] = 'tests.test_djeneralize.settings'
-
 from django.db.models import Avg, F, Q
 from django.db.models.query import ValuesListQuerySet, ValuesQuerySet
 from fixture.django_testcase import FixtureTestCase
@@ -29,8 +25,8 @@
 
 from djeneralize.models import BaseGeneralizationModel
 from djeneralize.utils import *
-from .fixtures import *
-from .test_djeneralize.writing.models import *
+from test_djeneralize.fixtures import *
+from test_djeneralize.writing.models import *
 
 
 class TestManager(FixtureTestCase):
@@ -276,4 +272,4 @@ def test_complex_query(self):
             q_small | q_large
             )
 
-        self._check_attributes(normal_objects, specialized_objects)
+        self._check_attributes(normal_objects, specialized_objects)

tests/test_managers.py → tests/test_djeneralize/tests/test_managers.py

@@ -1,17 +1,13 @@
 """Test suite to ensure that correct copying of managers"""
 
-import os
-# Ensure that Django knows where the project is:
-os.environ['DJANGO_SETTINGS_MODULE'] = 'tests.test_djeneralize.settings'
-
 from django.db.models.manager import Manager
 from fixture.django_testcase import FixtureTestCase
 from nose.tools import (
     eq_, ok_, assert_false, raises, assert_raises, assert_not_equal
     )
 
 from djeneralize.manager import SpecializationManager
-from .test_djeneralize.fruit.models import *
+from test_djeneralize.fruit.models import *
 
 
 class TestManager(object):
@@ -73,4 +69,4 @@ def test_specialized_not_inherit_specialized_managers(self):
 
         eq_(Apple.specializations.__class__, SpecializationManager)
         eq_(Banana.specializations.__class__, SpecializationManager)
-
+