diff --git a/deckhand/barbican/client_wrapper.py b/deckhand/barbican/client_wrapper.py
index c4594e5f..5f418829 100644
--- a/deckhand/barbican/client_wrapper.py
+++ b/deckhand/barbican/client_wrapper.py
@@ -14,6 +14,7 @@
 
 from keystoneauth1.identity import v3
 from keystoneauth1 import session
+from oslo_log import log as logging
 
 from deckhand.conf import config
 from deckhand import errors
@@ -22,6 +23,7 @@ from barbicanclient import barbican
 from barbicanclient import exceptions as barbican_exc
 
 CONF = config.CONF
+LOG = logging.getLogger(__name__)
 
 
 class BarbicanClientWrapper(object):
@@ -41,8 +43,8 @@ class BarbicanClientWrapper(object):
         if retry_on_conflict and self._cached_client is not None:
             return self._cached_client
 
-        # TODO: Deckhand's configuration file needs to be populated with
-        # correct Keysone authentication values as well as the Barbican
+        # TODO(fmontei): Deckhand's configuration file needs to be populated
+        # with correct Keysone authentication values as well as the Barbican
         # endpoint URL automatically.
         barbican_url = (CONF.barbican.api_endpoint
                         if CONF.barbican.api_endpoint
@@ -53,7 +55,7 @@ class BarbicanClientWrapper(object):
         sess = session.Session(auth=auth)
 
         try:
-            # TODO: replace with ``barbican_url``.
+            # TODO(fmontei): replace with ``barbican_url``.
             cli = barbican.client.Client(endpoint=barbican_url,
                                          session=sess)
             # Cache the client so we don't have to reconstruct and
@@ -63,7 +65,7 @@ class BarbicanClientWrapper(object):
 
         except barbican_exc.HTTPAuthError:
             msg = _("Unable to authenticate Barbican client.")
-            # TODO: Log the error.
+            # TODO(fmontei): Log the error.
             raise errors.ApiError(msg)
 
         return cli
@@ -106,9 +108,8 @@ class BarbicanClientWrapper(object):
                 # client and the next try will start with a fresh one.
                 if not attempt:
                     self._invalidate_cached_client()
-                    # TODO: include after implementing oslo.log.
-                    # LOG.debug("The Barbican client became unauthorized. "
-                    #           "Will attempt to reauthorize and try again.")
+                    LOG.debug("The Barbican client became unauthorized. "
+                              "Will attempt to reauthorize and try again.")
                 else:
                     # This code should be unreachable actually
                     raise
diff --git a/deckhand/control/api.py b/deckhand/control/api.py
index e36815ec..b6807097 100644
--- a/deckhand/control/api.py
+++ b/deckhand/control/api.py
@@ -37,7 +37,7 @@ def __setup_logging():
 
     logging.register_options(CONF)
     config.parse_args()
-    
+
     current_path = os.path.dirname(os.path.realpath(__file__))
     root_path = os.path.abspath(os.path.join(current_path, os.pardir,
                                              os.pardir))
diff --git a/deckhand/control/common.py b/deckhand/control/common.py
index 67c214b7..738b1e5a 100644
--- a/deckhand/control/common.py
+++ b/deckhand/control/common.py
@@ -26,6 +26,6 @@ class ViewBuilder(object):
     _collection_name = None
 
     def _gen_url(self, revision):
-        # TODO: Use a config-based url for the base url below.
+        # TODO(fmontei): Use a config-based url for the base url below.
         base_url = 'https://deckhand/api/v1.0/%s/%s'
         return base_url % (self._collection_name, revision.get('id'))
diff --git a/deckhand/control/documents.py b/deckhand/control/documents.py
index b9ed2223..1549d4a6 100644
--- a/deckhand/control/documents.py
+++ b/deckhand/control/documents.py
@@ -12,14 +12,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import copy
 import yaml
 
 import falcon
 
 from oslo_db import exception as db_exc
 from oslo_log import log as logging
-from oslo_serialization import jsonutils as json
 
 from deckhand.control import base as api_base
 from deckhand.db.sqlalchemy import api as db_api
diff --git a/deckhand/control/revision_documents.py b/deckhand/control/revision_documents.py
index d4394869..0e84d0e3 100644
--- a/deckhand/control/revision_documents.py
+++ b/deckhand/control/revision_documents.py
@@ -13,7 +13,6 @@
 # limitations under the License.
 
 import falcon
-from oslo_db import exception as db_exc
 
 from deckhand.control import base as api_base
 from deckhand.db.sqlalchemy import api as db_api
@@ -25,7 +24,7 @@ class RevisionDocumentsResource(api_base.BaseResource):
 
     def on_get(self, req, resp, revision_id):
         """Returns all documents for a `revision_id`.
-        
+
         Returns a multi-document YAML response containing all the documents
         matching the filters specified via query string parameters. Returned
         documents will be as originally posted with no substitutions or
diff --git a/deckhand/control/revisions.py b/deckhand/control/revisions.py
index e69031d2..6db1a3ed 100644
--- a/deckhand/control/revisions.py
+++ b/deckhand/control/revisions.py
@@ -25,7 +25,7 @@ class RevisionsResource(api_base.BaseResource):
 
     def on_get(self, req, resp, revision_id=None):
         """Returns list of existing revisions.
-        
+
         Lists existing revisions and reports basic details including a summary
         of validation status for each `deckhand/ValidationPolicy` that is part
         of each revision.
diff --git a/deckhand/control/views/revision.py b/deckhand/control/views/revision.py
index e0052552..b957d605 100644
--- a/deckhand/control/views/revision.py
+++ b/deckhand/control/views/revision.py
@@ -62,7 +62,7 @@ class ViewBuilder(common.ViewBuilder):
             'id': revision.get('id'),
             'createdAt': revision.get('created_at'),
             'url': self._gen_url(revision),
-            # TODO: Not yet implemented.
+            # TODO(fmontei): Not yet implemented.
             'validationPolicies': validation_policies,
             'status': success_status
         }
diff --git a/deckhand/db/sqlalchemy/api.py b/deckhand/db/sqlalchemy/api.py
index 355fae7d..3609cf16 100644
--- a/deckhand/db/sqlalchemy/api.py
+++ b/deckhand/db/sqlalchemy/api.py
@@ -17,7 +17,6 @@
 
 import ast
 import copy
-import datetime
 import threading
 
 from oslo_config import cfg
@@ -25,16 +24,8 @@ from oslo_db import exception as db_exception
 from oslo_db import options
 from oslo_db.sqlalchemy import session
 from oslo_log import log as logging
-from oslo_utils import excutils
 import six
-from six.moves import range
-import sqlalchemy
-from sqlalchemy.ext.compiler import compiles
-from sqlalchemy import desc
-from sqlalchemy import MetaData, Table
 import sqlalchemy.orm as sa_orm
-from sqlalchemy import sql
-import sqlalchemy.sql as sa_sql
 
 from deckhand.db.sqlalchemy import models
 from deckhand import errors
@@ -82,22 +73,6 @@ def get_session(autocommit=True, expire_on_commit=False):
                               expire_on_commit=expire_on_commit)
 
 
-def _validate_db_int(**kwargs):
-    """Make sure that all arguments are less than or equal to 2 ** 31 - 1.
-    This limitation is introduced because databases stores INT in 4 bytes.
-    If the validation fails for some argument, exception. Invalid is raised
-    with appropriate information.
-    """
-    max_int = (2 ** 31) - 1
-
-    for param_key, param_value in kwargs.items():
-        if param_value and param_value > max_int:
-            msg = _("'%(param)s' value out of range, "
-                    "must not exceed %(max)d.") % {"param": param_key,
-                                                   "max": max_int}
-            raise exception.Invalid(msg)
-
-
 def clear_db_env():
     """Unset global configuration variables for database."""
     global _FACADE
@@ -255,7 +230,7 @@ def _filter_revision_documents(documents, **filters):
 
     :returns: list of documents that match specified filters.
     """
-    # TODO: Implement this as an sqlalchemy query.
+    # TODO(fmontei): Implement this as an sqlalchemy query.
     filtered_documents = []
 
     for document in documents:
diff --git a/deckhand/db/sqlalchemy/models.py b/deckhand/db/sqlalchemy/models.py
index 7bcac00c..523f8a1b 100644
--- a/deckhand/db/sqlalchemy/models.py
+++ b/deckhand/db/sqlalchemy/models.py
@@ -23,12 +23,9 @@ from sqlalchemy import DateTime
 from sqlalchemy.ext import declarative
 from sqlalchemy import ForeignKey
 from sqlalchemy import Integer
-from sqlalchemy import orm
-from sqlalchemy.orm import backref, relationship
+from sqlalchemy.orm import relationship
 from sqlalchemy import schema
 from sqlalchemy import String
-from sqlalchemy import Text
-from sqlalchemy.types import TypeDecorator
 
 
 # Declarative base class which maintains a catalog of classes and tables
@@ -121,7 +118,8 @@ class Revision(BASE, DeckhandBase):
 
 class DocumentMixin(object):
     """Mixin class for sharing common columns across all document resources
-    such as documents themselves, layering policies and validation policies."""
+    such as documents themselves, layering policies and validation policies.
+    """
 
     name = Column(String(64), nullable=False)
     schema = Column(String(64), nullable=False)
diff --git a/deckhand/engine/document_validation.py b/deckhand/engine/document_validation.py
index 9acf665d..b5f42518 100644
--- a/deckhand/engine/document_validation.py
+++ b/deckhand/engine/document_validation.py
@@ -120,7 +120,7 @@ class DocumentValidation(object):
         validation_policy_factory = factories.ValidationPolicyFactory()
 
         for document in self.documents:
-            document_validations = self._validate_one(document)
+            self._validate_one(document)
 
         deckhand_schema_validation = validation_policy_factory.gen(
             types.DECKHAND_SCHEMA_VALIDATION, status='success')
@@ -156,12 +156,12 @@ class DocumentValidation(object):
                     document_type=document['schema'])
             else:
                 LOG.info('Skipping schema validation for abstract '
-                         'document: %s.' % document)
+                         'document: %s.', document)
 
     def _is_abstract(self, document):
         try:
             is_abstract = document['metadata']['layeringDefinition'][
-                'abstract'] == True
+                'abstract'] is True
             return is_abstract
         # NOTE(fmontei): If the document is of ``document_schema`` type and
         # no "layeringDefinition" or "abstract" property is found, then treat
diff --git a/deckhand/factories.py b/deckhand/factories.py
index 2322e721..29e03ddb 100644
--- a/deckhand/factories.py
+++ b/deckhand/factories.py
@@ -14,6 +14,7 @@
 
 import abc
 import copy
+import six
 
 from oslo_log import log as logging
 
@@ -23,8 +24,8 @@ from deckhand import types
 LOG = logging.getLogger(__name__)
 
 
+@six.add_metaclass(abc.ABCMeta)
 class DeckhandFactory(object):
-    __metaclass__ = abc.ABCMeta
 
     @abc.abstractmethod
     def gen(self, *args):
diff --git a/deckhand/tests/functional/base.py b/deckhand/tests/functional/base.py
index 4ff9c45b..1ecd1f43 100644
--- a/deckhand/tests/functional/base.py
+++ b/deckhand/tests/functional/base.py
@@ -14,7 +14,6 @@
 
 import mock
 
-import falcon
 from falcon import testing as falcon_testing
 
 from deckhand.control import api
diff --git a/deckhand/tests/functional/test_documents.py b/deckhand/tests/functional/test_documents.py
index ed9cbf0b..301d1fa2 100644
--- a/deckhand/tests/functional/test_documents.py
+++ b/deckhand/tests/functional/test_documents.py
@@ -17,9 +17,7 @@ import yaml
 
 import falcon
 
-from deckhand.control import api
 from deckhand.tests.functional import base as test_base
-from deckhand import types
 
 
 class TestDocumentsApi(test_base.TestFunctionalBase):
@@ -38,10 +36,6 @@ class TestDocumentsApi(test_base.TestFunctionalBase):
         result = self.app.simulate_post('/api/v1.0/documents', body=yaml_data)
         self.assertEqual(falcon.HTTP_201, result.status)
 
-        expected_documents = [yaml.safe_load(yaml_data)]
-        expected_validation_policy = self.validation_policy_factory.gen(
-            types.DECKHAND_SCHEMA_VALIDATION, status='success')
-
         # Validate that the correct number of documents were created: one
         # document corresponding to ``yaml_data``.
         resp_documents = [d for d in yaml.safe_load_all(result.text)]
diff --git a/deckhand/tests/unit/base.py b/deckhand/tests/unit/base.py
index ad69e0a6..22a7571e 100644
--- a/deckhand/tests/unit/base.py
+++ b/deckhand/tests/unit/base.py
@@ -17,9 +17,7 @@ from oslo_config import cfg
 from oslo_log import log as logging
 import testtools
 
-from deckhand.conf import config
 from deckhand.db.sqlalchemy import api as db_api
-from deckhand.db.sqlalchemy import models as db_models
 
 CONF = cfg.CONF
 logging.register_options(CONF)
diff --git a/deckhand/tests/unit/db/base.py b/deckhand/tests/unit/db/base.py
index 8749c938..32b2cffd 100644
--- a/deckhand/tests/unit/db/base.py
+++ b/deckhand/tests/unit/db/base.py
@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import testtools
 from testtools import matchers
 
 from deckhand.db.sqlalchemy import api as db_api
diff --git a/deckhand/tests/unit/db/test_revisions.py b/deckhand/tests/unit/db/test_revisions.py
index b153e011..1afd4dd0 100644
--- a/deckhand/tests/unit/db/test_revisions.py
+++ b/deckhand/tests/unit/db/test_revisions.py
@@ -12,8 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from deckhand.tests.unit.db import base
 from deckhand import factories
+from deckhand.tests.unit.db import base
 from deckhand import types
 
 
diff --git a/deckhand/tests/unit/engine/base.py b/deckhand/tests/unit/engine/base.py
index b4922fa3..71e2a9fd 100644
--- a/deckhand/tests/unit/engine/base.py
+++ b/deckhand/tests/unit/engine/base.py
@@ -16,11 +16,6 @@ import copy
 import os
 import yaml
 
-import mock
-import six
-
-from deckhand.engine import document_validation
-from deckhand import errors
 from deckhand.tests.unit import base as test_base
 
 
diff --git a/deckhand/tests/unit/resources/sample_layering_policy.yaml b/deckhand/tests/unit/resources/sample_layering_policy.yaml
index de0a7a98..5a1391bc 100644
--- a/deckhand/tests/unit/resources/sample_layering_policy.yaml
+++ b/deckhand/tests/unit/resources/sample_layering_policy.yaml
@@ -2,7 +2,7 @@
 ---
 schema: deckhand/LayeringPolicy/v1.0
 metadata:
-  schema: metadata/Control/v1
+  schema: metadata/Control/v1.0
   name: a-unique-config-name-12345
 data:
   layerOrder:
diff --git a/deckhand/tests/unit/views/test_views.py b/deckhand/tests/unit/views/test_views.py
index f6b73d96..4441bb26 100644
--- a/deckhand/tests/unit/views/test_views.py
+++ b/deckhand/tests/unit/views/test_views.py
@@ -14,8 +14,8 @@
 
 from deckhand.control.views import revision
 from deckhand import factories
-from deckhand.tests.unit.db import base
 from deckhand.tests import test_utils
+from deckhand.tests.unit.db import base
 from deckhand import types
 
 
@@ -103,9 +103,6 @@ class TestRevisionViews(base.TestDbBase):
 
         expected_attrs = ('id', 'url', 'createdAt', 'validationPolicies',
                           'status')
-        expected_validation_policies = [
-            {'name': 'deckhand-schema-validation'}, 'status'
-        ]
 
         for attr in expected_attrs:
             self.assertIn(attr, revision_view)
@@ -118,7 +115,6 @@ class TestRevisionViews(base.TestDbBase):
         self.assertEqual(revision_view['validationPolicies'][0]['status'],
                          'success')
 
-
     def test_show_revision_failed_validation_policy(self):
         # Simulate 4 document payload with an internally generated validation
         # policy which executes 'deckhand-schema-validation'.
@@ -134,9 +130,6 @@ class TestRevisionViews(base.TestDbBase):
 
         expected_attrs = ('id', 'url', 'createdAt', 'validationPolicies',
                           'status')
-        expected_validation_policies = [
-            {'name': 'deckhand-schema-validation'}, 'status'
-        ]
 
         for attr in expected_attrs:
             self.assertIn(attr, revision_view)
diff --git a/requirements.txt b/requirements.txt
index 9f2c0bab..76e705ed 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,10 @@
+# The order of packages is significant, because pip processes them in the order
+# of appearance. Changing the order has an impact on the overall integration
+# process, which may cause wedges in the gate later.
+
+# Hacking already pins down pep8, pyflakes and flake8
+hacking!=0.13.0,<0.14,>=0.12.0 # Apache-2.0
+
 falcon==1.1.0
 
 jsonschema!=2.5.0,<3.0.0,>=2.0.0 # MIT
diff --git a/test-requirements.txt b/test-requirements.txt
index da76afd5..5e85168c 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,3 +1,10 @@
+# The order of packages is significant, because pip processes them in the order
+# of appearance. Changing the order has an impact on the overall integration
+# process, which may cause wedges in the gate later.
+
+# Hacking already pins down pep8, pyflakes and flake8
+hacking!=0.13.0,<0.14,>=0.12.0 # Apache-2.0
+
 falcon==1.1.0
 
 mock>=2.0
diff --git a/tox.ini b/tox.ini
index 4c0840c6..462fc91f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -47,5 +47,6 @@ commands = flake8 {posargs}
 [flake8]
 # D100-104 deal with docstrings in public functions
 # D205, D400, D401 deal with docstring formatting
-ignore=E121,E122,E123,E124,E125,E126,E127,E128,E129,E131,E251,H405,D100,D101,D102,D103,D104,D205,D400,D401,H101,I100
-exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build,tools/xenserver*,releasenotes
+enable-extensions = H106,H203,H904
+ignore = E121,E122,E123,E124,E125,E126,E127,E128,E129,E131,E251,H405
+exclude =  .venv,.git,.tox,dist,*lib/python*,*egg,build,tools/xenserver*,releasenotes