PR feedback, fixes travis build.

.travis.yml

@@ -1,25 +1,15 @@
 language: python
 sudo: false
 
-matrix:
-  include:
-    - python: 2.7
-      env: NB_VERSION=notebook4
-    - python: 2.7
-      env: NB_VERSION=notebook5
-
-    - python: 3.4
-      env: NB_VERSION=notebook4
-    - python: 3.4
-      env: NB_VERSION=notebook5
-
-    - python: 3.6
-      env: NB_VERSION=notebook4
-    - python: 3.6
-      env: NB_VERSION=notebook5
-
-    - env: FLAKE8=true
-    - env: NOTEST=true
+python:
+  - "2.7"
+  - "3.4"
+  - "3.6"
+env:
+  - NB_VERSION=4
+  - NB_VERSION=5
+  - FLAKE8=true NB_VERSION=5
+  - NOTEST=true NB_VERSION=5
 
 addons:
   postgresql: "9.3"

pgcontents/pgmanager.py

@@ -57,6 +57,7 @@
     save_file,
 )
 from .utils.ipycompat import Bool, ContentsManager, from_dict
+from traitlets import default
 
 
 class PostgresContentsManager(PostgresManagerMixin, ContentsManager):
@@ -69,15 +70,18 @@ class PostgresContentsManager(PostgresManagerMixin, ContentsManager):
         help="Create a root directory automatically?",
     )
 
-    def _checkpoints_class_default(self):
+    @default('checkpoints_class')
+    def _default_checkpoints_class(self):
         return PostgresCheckpoints
 
-    def _checkpoints_kwargs_default(self):
+    @default('checkpoints_kwargs')
+    def _default_checkpoints_kwargs(self):
+        klass = PostgresContentsManager
         try:
-            klass = PostgresContentsManager
             kw = super(klass, self)._checkpoints_kwargs_default()
         except AttributeError:
-            kw = {'parent': self, 'log': self.log}
+            kw = super(klass, self)._default_checkpoints_kwargs()
+
         kw.update({
             'create_user_on_startup': self.create_user_on_startup,
             'crypto': self.crypto,
@@ -87,7 +91,8 @@ def _checkpoints_kwargs_default(self):
         })
         return kw
 
-    def _create_directory_on_startup_default(self):
+    @default('create_directory_on_startup')
+    def _default_create_directory_on_startup(self):
         return self.create_user_on_startup
 
     def __init__(self, *args, **kwargs):

pgcontents/tests/test_pgcontents_api.py

@@ -172,12 +172,12 @@ def test_list_checkpoints_sorting(self):
     # support backing up the deleted directory in the OS trash can.
     # FileContentsManager should allow non-empty directories to be deleted.
     def test_delete_non_empty_dir(self):
-        if issubclass(self.notebook.contents_manager_class,
+        if isinstance(self.notebook.contents_manager,
                       PostgresContentsManager):
             # make sure non-empty directories cannot be deleted with
             # PostgresContentsManager
             _test_delete_non_empty_dir_fail(self, u'å b')
-        elif issubclass(self.notebook.contents_manager_class,
+        elif isinstance(self.notebook.contents_manager,
                         HybridContentsManager):
             # check that one of the non-empty subdirectories owned by the
             # PostgresContentsManager cannnot be deleted