Changed the inheritance model to remove types

The inheritance model has changed, we no longer need to store an array of
`types` with the model we can just use the classname in `_cls`.

See the upgrade docs for information on how to upgrade
MongoEngine/mongoengine#148

tests/all_warnings/__init__.py

@@ -0,0 +1,104 @@
+"""
+This test has been put into a module.  This is because it tests warnings that
+only get triggered on first hit.  This way we can ensure its imported into the
+top level and called first by the test suite.
+"""
+
+import unittest
+import warnings
+
+from mongoengine import *
+
+
+__all__ = ('AllWarnings', )
+
+
+class AllWarnings(unittest.TestCase):
+
+    def setUp(self):
+        conn = connect(db='mongoenginetest')
+        self.warning_list = []
+        self.showwarning_default = warnings.showwarning
+        warnings.showwarning = self.append_to_warning_list
+
+    def append_to_warning_list(self, message, category, *args):
+        self.warning_list.append({"message": message,
+                                  "category": category})
+
+    def tearDown(self):
+        # restore default handling of warnings
+        warnings.showwarning = self.showwarning_default
+
+    def test_allow_inheritance_future_warning(self):
+        """Add FutureWarning for future allow_inhertiance default change.
+        """
+
+        class SimpleBase(Document):
+            a = IntField()
+
+        class InheritedClass(SimpleBase):
+            b = IntField()
+
+        InheritedClass()
+        self.assertEqual(len(self.warning_list), 1)
+        warning = self.warning_list[0]
+        self.assertEqual(FutureWarning, warning["category"])
+        self.assertTrue("InheritedClass" in str(warning["message"]))
+
+    def test_dbref_reference_field_future_warning(self):
+
+        class Person(Document):
+            name = StringField()
+            parent = ReferenceField('self')
+
+        Person.drop_collection()
+
+        p1 = Person()
+        p1.parent = None
+        p1.save()
+
+        p2 = Person(name="Wilson Jr")
+        p2.parent = p1
+        p2.save(cascade=False)
+
+        self.assertEqual(len(self.warning_list), 1)
+        warning = self.warning_list[0]
+        self.assertEqual(FutureWarning, warning["category"])
+        self.assertTrue("ReferenceFields will default to using ObjectId"
+                        in str(warning["message"]))
+
+    def test_document_save_cascade_future_warning(self):
+
+        class Person(Document):
+            name = StringField()
+            parent = ReferenceField('self')
+
+        Person.drop_collection()
+
+        p1 = Person(name="Wilson Snr")
+        p1.parent = None
+        p1.save()
+
+        p2 = Person(name="Wilson Jr")
+        p2.parent = p1
+        p2.parent.name = "Poppa Wilson"
+        p2.save()
+
+        self.assertEqual(len(self.warning_list), 1)
+        warning = self.warning_list[0]
+        self.assertEqual(FutureWarning, warning["category"])
+        self.assertTrue("Cascading saves will default to off in 0.8"
+                        in str(warning["message"]))
+
+    def test_document_collection_syntax_warning(self):
+
+        class NonAbstractBase(Document):
+            pass
+
+        class InheritedDocumentFailTest(NonAbstractBase):
+            meta = {'collection': 'fail'}
+
+        warning = self.warning_list[0]
+        self.assertEqual(SyntaxWarning, warning["category"])
+        self.assertEqual('non_abstract_base',
+                         InheritedDocumentFailTest._get_collection_name())