diff --git a/.zuul.yaml b/.zuul.yaml
index c4681084..759ee9d6 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -89,8 +89,10 @@
         - tox-pep8
         - tox-py36:
             timeout: 6000
+            nodeset: ubuntu-bionic
         - tox-py37:
             timeout: 6000
+            nodeset: ubuntu-bionic
         - tox-py38:
             timeout: 6000
         - opendev-buildset-registry
@@ -101,8 +103,10 @@
         - tox-pep8
         - tox-py36:
             timeout: 6000
+            nodeset: ubuntu-bionic
         - tox-py37:
             timeout: 6000
+            nodeset: ubuntu-bionic
         - tox-py38:
             timeout: 6000
         - opendev-buildset-registry
diff --git a/doc/requirements.txt b/doc/requirements.txt
index aea0a6e9..d5e78edc 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -1,6 +1,8 @@
 # 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.
+jinja2<3.0.0
+MarkupSafe<2.1.0
 sphinx<2.0.0
 sphinxcontrib-pecanwsme>=0.5
 openstackdocstheme
diff --git a/storyboard/db/models.py b/storyboard/db/models.py
index 1fb8f77b..ad876d2e 100644
--- a/storyboard/db/models.py
+++ b/storyboard/db/models.py
@@ -310,6 +310,45 @@ story_storytags = Table(
 )
 
 
+# Time-line models
+
+class TimeLineEvent(ModelBuilder, Base):
+    __tablename__ = 'events'
+
+    story_id = Column(Integer, ForeignKey('stories.id'), nullable=True)
+    worklist_id = Column(Integer, ForeignKey('worklists.id'), nullable=True)
+    board_id = Column(Integer, ForeignKey('boards.id'), nullable=True)
+    comment_id = Column(Integer, ForeignKey('comments.id'), nullable=True)
+    comment = relationship('Comment', backref='event')
+    author_id = Column(Integer, ForeignKey('users.id'), nullable=True)
+
+    event_type = Column(Enum(*event_types.ALL), nullable=False)
+
+    # this info field should contain additional fields to describe the event
+    # ex. {'old_status': 'Todo', 'new_status': 'In progress'}
+    # or {'old_assignee_id': 1, 'new_assignee_id': 42}
+    event_info = Column(UnicodeText(), nullable=True)
+
+
+class Comment(FullText, ModelBuilder, Base):
+    __fulltext_columns__ = ['content']
+
+    id = Column(Integer, primary_key=True)
+    content = Column(MYSQL_MEDIUM_TEXT)
+    is_active = Column(Boolean, default=True)
+    in_reply_to = Column(Integer, ForeignKey('comments.id'))
+    parent = relationship('Comment', remote_side=[id], backref='children')
+
+
+class HistoricalComment(FullText, ModelBuilder, Base):
+    __tablename__ = 'comments_history'
+    __fulltext_columns__ = ['content']
+
+    content = Column(MYSQL_MEDIUM_TEXT)
+    comment_id = Column(Integer, ForeignKey('comments.id'), nullable=False)
+    current = relationship(Comment, backref='history')
+
+
 class Story(FullText, ModelBuilder, Base):
     __tablename__ = 'stories'
 
@@ -526,45 +565,6 @@ class StorySummary(Base):
                       "task_statuses"]
 
 
-# Time-line models
-
-class TimeLineEvent(ModelBuilder, Base):
-    __tablename__ = 'events'
-
-    story_id = Column(Integer, ForeignKey('stories.id'), nullable=True)
-    worklist_id = Column(Integer, ForeignKey('worklists.id'), nullable=True)
-    board_id = Column(Integer, ForeignKey('boards.id'), nullable=True)
-    comment_id = Column(Integer, ForeignKey('comments.id'), nullable=True)
-    comment = relationship('Comment', backref='event')
-    author_id = Column(Integer, ForeignKey('users.id'), nullable=True)
-
-    event_type = Column(Enum(*event_types.ALL), nullable=False)
-
-    # this info field should contain additional fields to describe the event
-    # ex. {'old_status': 'Todo', 'new_status': 'In progress'}
-    # or {'old_assignee_id': 1, 'new_assignee_id': 42}
-    event_info = Column(UnicodeText(), nullable=True)
-
-
-class Comment(FullText, ModelBuilder, Base):
-    __fulltext_columns__ = ['content']
-
-    id = Column(Integer, primary_key=True)
-    content = Column(MYSQL_MEDIUM_TEXT)
-    is_active = Column(Boolean, default=True)
-    in_reply_to = Column(Integer, ForeignKey('comments.id'))
-    parent = relationship('Comment', remote_side=[id], backref='children')
-
-
-class HistoricalComment(FullText, ModelBuilder, Base):
-    __tablename__ = 'comments_history'
-    __fulltext_columns__ = ['content']
-
-    content = Column(MYSQL_MEDIUM_TEXT)
-    comment_id = Column(Integer, ForeignKey('comments.id'), nullable=False)
-    current = relationship(Comment, backref='history')
-
-
 # Subscription and notifications
 
 class Subscription(ModelBuilder, Base):
diff --git a/storyboard/db/projects_loader.py b/storyboard/db/projects_loader.py
index 4a542a8a..61996d1a 100644
--- a/storyboard/db/projects_loader.py
+++ b/storyboard/db/projects_loader.py
@@ -38,7 +38,7 @@ LOG = log.getLogger(__name__)
 def do_load_models(filename):
     config_file = open(filename)
     session = db_api.get_session(autocommit=False, in_request=False)
-    projects_list = yaml.load(config_file)
+    projects_list = yaml.safe_load(config_file)
 
     project_groups = list()
 
diff --git a/storyboard/tests/api/test_project_groups.py b/storyboard/tests/api/test_project_groups.py
index d908218b..1b37043a 100644
--- a/storyboard/tests/api/test_project_groups.py
+++ b/storyboard/tests/api/test_project_groups.py
@@ -151,7 +151,7 @@ class TestProjectGroupSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(1, len(results.json))
         self.assertEqual('1', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual('projectgroup2', result['name'])
@@ -164,7 +164,7 @@ class TestProjectGroupSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -179,7 +179,7 @@ class TestProjectGroupSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -196,7 +196,7 @@ class TestProjectGroupSearch(base.FunctionalTest):
         self.assertEqual(1, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
         self.assertEqual('1', results.headers['X-Limit'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -224,7 +224,7 @@ class TestProjectGroupSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(3, len(results.json))
         self.assertEqual('3', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(3, result['id'])
@@ -242,7 +242,7 @@ class TestProjectGroupSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(3, len(results.json))
         self.assertEqual('3', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -259,4 +259,4 @@ class TestProjectGroupSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(0, len(results.json))
         self.assertEqual('0', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
diff --git a/storyboard/tests/api/test_projects.py b/storyboard/tests/api/test_projects.py
index 6b1ea10b..e9c6a7eb 100644
--- a/storyboard/tests/api/test_projects.py
+++ b/storyboard/tests/api/test_projects.py
@@ -143,7 +143,7 @@ class TestProjectSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(3, len(results.json))
         self.assertEqual('3', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
     def test_search_by_name(self):
         url = self.build_search_url({
@@ -153,7 +153,7 @@ class TestProjectSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(1, len(results.json))
         self.assertEqual('1', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual('project1', result['name'])
@@ -166,7 +166,7 @@ class TestProjectSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -181,7 +181,7 @@ class TestProjectSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(2, result['id'])
@@ -197,7 +197,7 @@ class TestProjectSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(1, len(results.json))
         self.assertEqual('1', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(2, result['id'])
@@ -210,7 +210,7 @@ class TestProjectSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(0, len(results.json))
         self.assertEqual('0', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
     def test_search_limit(self):
         url = self.build_search_url({
@@ -222,7 +222,7 @@ class TestProjectSearch(base.FunctionalTest):
         self.assertEqual(1, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
         self.assertEqual('1', results.headers['X-Limit'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -250,7 +250,7 @@ class TestProjectSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(3, len(results.json))
         self.assertEqual('3', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(3, result['id'])
@@ -268,7 +268,7 @@ class TestProjectSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(3, len(results.json))
         self.assertEqual('3', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -285,4 +285,4 @@ class TestProjectSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(0, len(results.json))
         self.assertEqual('0', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
diff --git a/storyboard/tests/api/test_stories.py b/storyboard/tests/api/test_stories.py
index d3cb1bed..6995fd30 100644
--- a/storyboard/tests/api/test_stories.py
+++ b/storyboard/tests/api/test_stories.py
@@ -253,7 +253,7 @@ class TestStorySearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(5, len(results.json))
         self.assertEqual('5', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
     def test_search_by_title(self):
         url = self.build_search_url({
@@ -263,7 +263,7 @@ class TestStorySearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -278,7 +278,7 @@ class TestStorySearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -293,7 +293,7 @@ class TestStorySearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(1, len(results.json))
         self.assertEqual('1', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -304,7 +304,7 @@ class TestStorySearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -319,7 +319,7 @@ class TestStorySearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -334,7 +334,7 @@ class TestStorySearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -349,7 +349,7 @@ class TestStorySearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(1, len(results.json))
         self.assertEqual('1', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -401,7 +401,7 @@ class TestStorySearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(0, len(results.json))
         self.assertEqual('0', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
     def test_search_limit(self):
         url = self.build_search_url({
@@ -413,7 +413,7 @@ class TestStorySearch(base.FunctionalTest):
         self.assertEqual(1, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
         self.assertEqual('1', results.headers['X-Limit'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -441,7 +441,7 @@ class TestStorySearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(5, len(results.json))
         self.assertEqual('5', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(5, result['id'])
@@ -463,7 +463,7 @@ class TestStorySearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(5, len(results.json))
         self.assertEqual('5', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
diff --git a/storyboard/tests/api/test_task_statuses.py b/storyboard/tests/api/test_task_statuses.py
index 8f6e90b8..4b10d265 100644
--- a/storyboard/tests/api/test_task_statuses.py
+++ b/storyboard/tests/api/test_task_statuses.py
@@ -36,7 +36,7 @@ class TestTaskStatusesSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(5, len(results.json))
         self.assertEqual('5', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
     def test_search_by_name(self):
         """Test searching by various names."""
@@ -49,7 +49,7 @@ class TestTaskStatusesSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(1, len(results.json))
         self.assertEqual('1', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         # Assert that searching by 'task status' or some permutation works.
         url = self.build_search_url({
@@ -59,7 +59,7 @@ class TestTaskStatusesSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(5, len(results.json))
         self.assertEqual('5', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         url = self.build_search_url({
             'name': 'stat'
@@ -68,7 +68,7 @@ class TestTaskStatusesSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(5, len(results.json))
         self.assertEqual('5', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
     def test_search_constrain(self):
         """Test constraint searches."""
diff --git a/storyboard/tests/api/test_tasks.py b/storyboard/tests/api/test_tasks.py
index f457855e..780b7a64 100644
--- a/storyboard/tests/api/test_tasks.py
+++ b/storyboard/tests/api/test_tasks.py
@@ -423,7 +423,7 @@ class TestTaskSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(4, len(results.json))
         self.assertEqual('4', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
     def test_search_by_title(self):
         url = self.build_search_url({
@@ -433,7 +433,7 @@ class TestTaskSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -448,7 +448,7 @@ class TestTaskSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(3, len(results.json))
         self.assertEqual('3', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -465,7 +465,7 @@ class TestTaskSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(1, len(results.json))
         self.assertEqual('1', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -478,7 +478,7 @@ class TestTaskSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(2, result['id'])
@@ -493,7 +493,7 @@ class TestTaskSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(3, len(results.json))
         self.assertEqual('3', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(2, result['id'])
@@ -510,7 +510,7 @@ class TestTaskSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(2, result['id'])
@@ -523,7 +523,7 @@ class TestTaskSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(3, len(results.json))
         self.assertEqual('3', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(2, result['id'])
@@ -540,7 +540,7 @@ class TestTaskSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -553,7 +553,7 @@ class TestTaskSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(2, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(2, result['id'])
@@ -568,7 +568,7 @@ class TestTaskSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(0, len(results.json))
         self.assertEqual('0', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
     def test_search_limit(self):
         url = self.build_search_url({
@@ -580,7 +580,7 @@ class TestTaskSearch(base.FunctionalTest):
         self.assertEqual(1, len(results.json))
         self.assertEqual('2', results.headers['X-Total'])
         self.assertEqual('1', results.headers['X-Limit'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -608,7 +608,7 @@ class TestTaskSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(4, len(results.json))
         self.assertEqual('4', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(1, result['id'])
@@ -628,7 +628,7 @@ class TestTaskSearch(base.FunctionalTest):
         results = self.get_json(url, expect_errors=True)
         self.assertEqual(4, len(results.json))
         self.assertEqual('4', results.headers['X-Total'])
-        self.assertFalse('X-Marker' in results.headers)
+        self.assertNotIn('X-Marker', results.headers)
 
         result = results.json[0]
         self.assertEqual(4, result['id'])
diff --git a/storyboard/tests/db/migration/test_unique_revisions.py b/storyboard/tests/db/migration/test_unique_revisions.py
index 4f565e4a..8c3a3ba4 100644
--- a/storyboard/tests/db/migration/test_unique_revisions.py
+++ b/storyboard/tests/db/migration/test_unique_revisions.py
@@ -43,13 +43,13 @@ class UniqueRevisionsTestCase(testtools.TestCase):
             module = imp.load_source('module', six.text_type(module_path))
             revision_id = module.revision
 
-            self.assertFalse(revision_id in revisions,
+            self.assertNotIn(revision_id, revisions,
                              "Found two revisions with id %s" % revision_id)
             revisions.add(revision_id)
 
             down_revision_id = module.revision
 
-            self.assertFalse(down_revision_id in down_revisions,
+            self.assertNotIn(down_revision_id, down_revisions,
                              "Found two revisions with down_revision_id %s"
                              % revision_id)
             down_revisions.add(down_revision_id)
diff --git a/storyboard/tests/plugin/test_user_preferences.py b/storyboard/tests/plugin/test_user_preferences.py
index 7cc76dd3..d6a94d96 100644
--- a/storyboard/tests/plugin/test_user_preferences.py
+++ b/storyboard/tests/plugin/test_user_preferences.py
@@ -53,9 +53,9 @@ class TestUserPreferencesPluginBase(base.TestCase):
         self.assertEqual(2, len(manager.extensions))
         manager.map(prefs_base.load_preferences, loaded_prefs)
 
-        self.assertTrue("foo" in loaded_prefs)
-        self.assertTrue("omg" in loaded_prefs)
-        self.assertTrue("lol" in loaded_prefs)
+        self.assertIn("foo", loaded_prefs)
+        self.assertIn("omg", loaded_prefs)
+        self.assertIn("lol", loaded_prefs)
 
         self.assertEqual(loaded_prefs["foo"], "baz")
         self.assertEqual(loaded_prefs["omg"], "wat")
diff --git a/tox.ini b/tox.ini
index 00b9d984..18f16cef 100644
--- a/tox.ini
+++ b/tox.ini
@@ -54,8 +54,9 @@ commands =
 # The following rules should either be addressed or determined to be
 # skippable long term.
 # E265 is ignored to make switch to newer hacking easier
+# H216 is ignored to allow use of the mock library instead of unittest.mock
 # H405 is ignored to make switch to newer hacking easier
-ignore = E125,E128,E265,H405,W503
+ignore = E125,E128,E265,H216,H405,W503
 builtins = _
 show-source = True
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build