diff --git a/plinth/context_processors.py b/plinth/context_processors.py
index e58d7e162..433e0dd4b 100644
--- a/plinth/context_processors.py
+++ b/plinth/context_processors.py
@@ -25,8 +25,7 @@ from plinth import cfg
 
 
 def common(request):
-    """
-    Add additional context values to RequestContext for use in templates.
+    """Add additional context values to RequestContext for use in templates.
 
     Any resources referenced in the return value are expected to have been
     initialized or configured externally beforehand.
diff --git a/plinth/tests/coverage/coverage.py b/plinth/tests/coverage/coverage.py
index aa22e7cbf..965bf3393 100644
--- a/plinth/tests/coverage/coverage.py
+++ b/plinth/tests/coverage/coverage.py
@@ -73,7 +73,7 @@ class CoverageCommand(setuptools.Command):
         # Erase any existing HTML report files
         try:
             shutil.rmtree(COVERAGE_REPORT_DIR, True)
-        except:
+        except Exception:
             pass
 
         # Run the coverage analysis
diff --git a/plinth/tests/data/django_test_settings.py b/plinth/tests/data/django_test_settings.py
index 894b60da3..8f2978c90 100644
--- a/plinth/tests/data/django_test_settings.py
+++ b/plinth/tests/data/django_test_settings.py
@@ -1,7 +1,28 @@
-# Django settings for test modules.
+#
+# This file is part of Plinth.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+Django settings for test modules.
+"""
 
 import os
+
 TEST_DATA_DIR = os.path.dirname(os.path.abspath(__file__))
+
 DATABASES = {
     'default': {
         'ENGINE': 'django.db.backends.sqlite3',
@@ -9,8 +30,6 @@ DATABASES = {
     }
 }
 
-DEFAULT_INDEX_TABLESPACE = ''
-
 INSTALLED_APPS = (
     'plinth',
 )
diff --git a/plinth/tests/runtests.py b/plinth/tests/runtests.py
index 6aabc7862..992b82509 100644
--- a/plinth/tests/runtests.py
+++ b/plinth/tests/runtests.py
@@ -16,7 +16,9 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
-"""Module for Django pre-test configuration and setup."""
+"""
+Module for Django pre-test configuration and setup.
+"""
 
 import os
 import sys
@@ -28,7 +30,7 @@ from django.test.utils import get_runner
 
 def run_tests(pattern=None, return_to_caller=False):
     """Set up the Django test environment and run the specified tests."""
-    os.environ['DJANGO_SETTINGS_MODULE'] =\
+    os.environ['DJANGO_SETTINGS_MODULE'] = \
         'plinth.tests.data.django_test_settings'
     django.setup()
     TestRunner = get_runner(settings)
@@ -36,6 +38,7 @@ def run_tests(pattern=None, return_to_caller=False):
 
     if pattern is None:
         pattern = 'plinth.tests'
+
     failures = test_runner.run_tests([pattern])
     if failures > 0 or not return_to_caller:
         sys.exit(bool(failures))
diff --git a/plinth/tests/test_actions.py b/plinth/tests/test_actions.py
index 4da222834..1cc70724c 100644
--- a/plinth/tests/test_actions.py
+++ b/plinth/tests/test_actions.py
@@ -1,5 +1,3 @@
-#!/usr/bin/python3
-# -*- mode: python; mode: auto-fill; fill-column: 80 -*-
 #
 # This file is part of Plinth.
 #
@@ -17,6 +15,10 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+"""
+Test module for actions utilities that modify configuration.
+"""
+
 import os
 import shutil
 import unittest
@@ -45,8 +47,8 @@ class TestPrivileged(unittest.TestCase):
 
     @classmethod
     def tearDownClass(cls):
-        os.remove('actions/echo')
-        os.remove('actions/id')
+        os.remove(os.path.join(cfg.actions_dir, 'echo'))
+        os.remove(os.path.join(cfg.actions_dir, 'id'))
 
     def notest_run_as_root(self):
         """1. Privileged actions run as root. """
@@ -141,8 +143,3 @@ class TestPrivileged(unittest.TestCase):
         output = run('echo', tuple(options.split()))
         output = output.rstrip('\n')
         self.assertEqual(options, output)
-
-
-
-if __name__ == "__main__":
-    unittest.main()
diff --git a/plinth/tests/test_cfg.py b/plinth/tests/test_cfg.py
index c5f9ab27b..e491a0a0b 100644
--- a/plinth/tests/test_cfg.py
+++ b/plinth/tests/test_cfg.py
@@ -1,4 +1,3 @@
-#!/usr/bin/python3
 #
 # This file is part of Plinth.
 #
@@ -16,6 +15,10 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+"""
+Test module for configuration module.
+"""
+
 import configparser
 import os
 import shutil
@@ -244,7 +247,3 @@ class CfgTestCase(unittest.TestCase):
         if os.path.isfile(TEST_CONFIG_FILE):
             os.remove(TEST_CONFIG_FILE)
         shutil.move(SAVED_CONFIG_FILE, TEST_CONFIG_FILE)
-
-
-if __name__ == '__main__':
-    unittest.main()
diff --git a/plinth/tests/test_context_processors.py b/plinth/tests/test_context_processors.py
index f3be34fab..b48a4f040 100644
--- a/plinth/tests/test_context_processors.py
+++ b/plinth/tests/test_context_processors.py
@@ -1,4 +1,3 @@
-#!/usr/bin/python3
 #
 # This file is part of Plinth.
 #
@@ -16,6 +15,10 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+"""
+Test module for Plinth's custom context processors.
+"""
+
 from django.http import HttpRequest
 from django.test import TestCase
 
diff --git a/plinth/tests/test_kvstore.py b/plinth/tests/test_kvstore.py
index fdf078bc0..8854f1a98 100644
--- a/plinth/tests/test_kvstore.py
+++ b/plinth/tests/test_kvstore.py
@@ -1,4 +1,3 @@
-#!/usr/bin/python3
 #
 # This file is part of Plinth.
 #
@@ -16,15 +15,19 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+"""
+Test module for key/value store.
+"""
+
 from django.test import TestCase
 
 from plinth import kvstore
 
 
-class KvstoreTestCase(TestCase):
+class KVStoreTestCase(TestCase):
     """Verify the behavior of the kvstore module."""
 
-    def test_get(self):
+    def test_get_set(self):
         """Verify that a set value can be retrieved."""
         key = 'name'
         expected_value = 'Guido'
@@ -32,6 +35,15 @@ class KvstoreTestCase(TestCase):
         actual_value = kvstore.get(key)
         self.assertEqual(expected_value, actual_value)
 
+    def test_get_set_complex_structures(self):
+        """Verify that complex structures can be stored and retrieved."""
+        key = 'compex_structure'
+        expected_value = {'k1': 1, 'k2': [2, 3], 'k3': 4.5, 'k4': 'Hello',
+                          'k5': {'a': 'b'}}
+        kvstore.set(key, expected_value)
+        actual_value = kvstore.get(key)
+        self.assertEqual(expected_value, actual_value)
+
     def test_get_default(self):
         """Verify that either a set value or its default can be retrieved."""
         expected = 'default'
diff --git a/plinth/tests/test_menu.py b/plinth/tests/test_menu.py
index dcb214d26..ccc9d52a3 100644
--- a/plinth/tests/test_menu.py
+++ b/plinth/tests/test_menu.py
@@ -1,4 +1,3 @@
-#!/usr/bin/python3
 #
 # This file is part of Plinth.
 #
@@ -16,6 +15,10 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+"""
+Test module for menus.
+"""
+
 from django.core.urlresolvers import reverse
 from django.http import HttpRequest
 from django.test import TestCase
@@ -38,9 +41,11 @@ def build_menu(size=5):
                           'Icon' + str(index),
                           URL_TEMPLATE.format(index, index, index),
                           random.randint(0, 1000)])
+
     menu = Menu()
     for data in item_data:
         menu.add_item(data[0], data[1], data[2], data[3])
+
     return menu
 
 
@@ -133,7 +138,9 @@ class MenuTestCase(TestCase):
         actual_item = menu.add_urlname(expected_label, expected_icon,
                                        expected_url, expected_order)
 
+        self.assertEqual(1, len(menu.items))
         self.assertIsNotNone(actual_item)
+        self.assertEqual(actual_item, menu.items[0])
         self.assertEqual(expected_label, actual_item.label)
         self.assertEqual(expected_icon, actual_item.icon)
         self.assertEqual(reversed_url, actual_item.url)
@@ -150,7 +157,9 @@ class MenuTestCase(TestCase):
         actual_item = menu.add_item(expected_label, expected_icon,
                                     expected_url, expected_order)
 
+        self.assertEqual(1, len(menu.items))
         self.assertIsNotNone(actual_item)
+        self.assertEqual(actual_item, menu.items[0])
         self.assertEqual(expected_label, actual_item.label)
         self.assertEqual(expected_icon, actual_item.icon)
         self.assertEqual(expected_url, actual_item.url)
diff --git a/plinth/tests/test_network.py b/plinth/tests/test_network.py
index 65b97e2ad..78c88a89d 100644
--- a/plinth/tests/test_network.py
+++ b/plinth/tests/test_network.py
@@ -1,4 +1,3 @@
-#!/usr/bin/python3
 #
 # This file is part of Plinth.
 #
@@ -16,6 +15,10 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+"""
+Test module for network configuration utilities.
+"""
+
 import os
 import unittest
 
@@ -116,7 +119,3 @@ class TestNetwork(unittest.TestCase):
         self.assertEqual(
             secrets['802-11-wireless-security']['psk'],
             'secretpassword')
-
-
-if __name__ == "__main__":
-    unittest.main()
diff --git a/plinth/tests/test_pagekite.py b/plinth/tests/test_pagekite.py
index 7463f25f5..613bc4c18 100644
--- a/plinth/tests/test_pagekite.py
+++ b/plinth/tests/test_pagekite.py
@@ -1,4 +1,3 @@
-#!/usr/bin/python3
 #
 # This file is part of Plinth.
 #
@@ -16,6 +15,10 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+"""
+Test modules for Pagekite functions.
+"""
+
 import unittest
 
 
diff --git a/plinth/tests/test_templatetags.py b/plinth/tests/test_templatetags.py
index 8f815cc6d..b24334d9c 100644
--- a/plinth/tests/test_templatetags.py
+++ b/plinth/tests/test_templatetags.py
@@ -15,6 +15,10 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+"""
+Test module for custom Django template tags.
+"""
+
 import unittest
 
 from plinth.templatetags.plinth_extras import mark_active_menuitem
@@ -30,7 +34,8 @@ class TestShowSubSubMenu(unittest.TestCase):
             else:
                 self.assertFalse(item['active'])
 
-    def _verify_active_menuitems(self, menu):
+    @staticmethod
+    def _verify_active_menuitems(menu):
         """Verify that one and only one menuitem is marked as active"""
         return sum([item['active'] for item in menu]) == 1