diff --git a/zaza/__init__.py b/zaza/__init__.py
index 5ffaf45..b113096 100644
--- a/zaza/__init__.py
+++ b/zaza/__init__.py
@@ -1,8 +1,9 @@
+"""Functions to support converting async function to a sync equivalent."""
 import asyncio
 
 
 def run(*steps):
-    """Run the given steps in an asyncio loop
+    """Run the given steps in an asyncio loop.
 
     :returns: The result of the asyncio.Task
     :rtype: Any
@@ -18,7 +19,7 @@ def run(*steps):
 
 
 def sync_wrapper(f):
-    """Convert the given async function into a sync function
+    """Convert the given async function into a sync function.
 
     :returns: The de-async'd function
     :rtype: function
diff --git a/zaza/charm_tests/__init__.py b/zaza/charm_tests/__init__.py
index e69de29..b2c4daa 100644
--- a/zaza/charm_tests/__init__.py
+++ b/zaza/charm_tests/__init__.py
@@ -0,0 +1 @@
+"""Collection of modules for testing a specific application."""
diff --git a/zaza/charm_tests/dragent/__init__.py b/zaza/charm_tests/dragent/__init__.py
index e69de29..19b1452 100644
--- a/zaza/charm_tests/dragent/__init__.py
+++ b/zaza/charm_tests/dragent/__init__.py
@@ -0,0 +1 @@
+"""Collection of code for setting up and testing BGP."""
diff --git a/zaza/charm_tests/dragent/configure.py b/zaza/charm_tests/dragent/configure.py
index 2091bfd..9cef2c2 100644
--- a/zaza/charm_tests/dragent/configure.py
+++ b/zaza/charm_tests/dragent/configure.py
@@ -1,4 +1,5 @@
 #!/usr/bin/env python3
+"""Setup for BGP deployments."""
 
 from zaza.configure import (
     network,
@@ -42,7 +43,7 @@ DEFAULT_UNDERCLOUD_NETWORK_CONFIG = {
 
 
 def setup():
-    """Setup BGP networking
+    """Run setup for BGP networking.
 
     Configure the following:
         The overcloud network using subnet pools
@@ -54,7 +55,6 @@ def setup():
     :returns: None
     :rtype: None
     """
-
     cli_utils.setup_logging()
 
     # Get network configuration settings
diff --git a/zaza/charm_tests/dragent/test.py b/zaza/charm_tests/dragent/test.py
index 28c766a..1c56c34 100644
--- a/zaza/charm_tests/dragent/test.py
+++ b/zaza/charm_tests/dragent/test.py
@@ -1,4 +1,5 @@
 #!/usr/bin/env python3
+"""Run BGP tests."""
 
 import argparse
 import logging
@@ -14,7 +15,7 @@ from zaza.utilities import (
 
 
 def test_bgp_routes(peer_application_name="quagga", keystone_session=None):
-    """Test BGP routes
+    """Test BGP routes.
 
     :param peer_application_name: String name of BGP peer application
     :type peer_application_name: string
@@ -24,7 +25,6 @@ def test_bgp_routes(peer_application_name="quagga", keystone_session=None):
     :returns: None
     :rtype: None
     """
-
     # If a session has not been provided, acquire one
     if not keystone_session:
         keystone_session = openstack_utils.get_overcloud_keystone_session()
@@ -66,12 +66,11 @@ def test_bgp_routes(peer_application_name="quagga", keystone_session=None):
 
 
 def run_from_cli():
-    """Run test for BGP routes from CLI
+    """Run test for BGP routes from CLI.
 
     :returns: None
     :rtype: None
     """
-
     cli_utils.setup_logging()
     parser = argparse.ArgumentParser()
     parser.add_argument("--peer-application", "-a",
diff --git a/zaza/charm_tests/dragent/tests.py b/zaza/charm_tests/dragent/tests.py
index 3d993c7..5e6957d 100644
--- a/zaza/charm_tests/dragent/tests.py
+++ b/zaza/charm_tests/dragent/tests.py
@@ -1,4 +1,5 @@
 #!/usr/bin/env python3
+"""Define class of BGP tests."""
 
 import unittest
 
@@ -7,14 +8,17 @@ from zaza.charm_tests.dragent import test
 
 
 class DRAgentTest(unittest.TestCase):
+    """Class to encapsulate BPG tests."""
 
     BGP_PEER_APPLICATION = 'quagga'
 
     @classmethod
     def setUpClass(cls):
+        """Run setup for BGP tests."""
         cli_utils.setup_logging()
 
     def test_bgp_routes(self):
+        """Run bgp tests."""
         test.test_bgp_routes(peer_application_name=self.BGP_PEER_APPLICATION)
 
 
diff --git a/zaza/charm_tests/glance/__init__.py b/zaza/charm_tests/glance/__init__.py
index e69de29..cdb6914 100644
--- a/zaza/charm_tests/glance/__init__.py
+++ b/zaza/charm_tests/glance/__init__.py
@@ -0,0 +1 @@
+"""Collection of code for setting up and testing glance."""
diff --git a/zaza/charm_tests/glance/setup.py b/zaza/charm_tests/glance/setup.py
index a7f0819..3216dbd 100644
--- a/zaza/charm_tests/glance/setup.py
+++ b/zaza/charm_tests/glance/setup.py
@@ -1,7 +1,10 @@
-#!/usr/bin/env python3
+"""Code for configuring glance."""
 
 
 def basic_setup():
-    """Glance setup for testing glance is currently part of glance functional
-       tests. Image setup for other tests to use should go here"""
+    """Run setup for testing glance.
+
+    Glance setup for testing glance is currently part of glance functional
+    tests. Image setup for other tests to use should go here.
+    """
     pass
diff --git a/zaza/charm_tests/glance/tests.py b/zaza/charm_tests/glance/tests.py
index 5861e12..76a6a4e 100644
--- a/zaza/charm_tests/glance/tests.py
+++ b/zaza/charm_tests/glance/tests.py
@@ -1,4 +1,5 @@
 #!/usr/bin/env python3
+"""Encapsulate glance testing."""
 
 import logging
 
@@ -7,15 +8,17 @@ import zaza.charm_tests.test_utils as test_utils
 
 
 class GlanceTest(test_utils.OpenStackBaseTest):
+    """Encapsulate glance tests."""
 
     @classmethod
     def setUpClass(cls):
+        """Run class setup for running glance tests."""
         super(GlanceTest, cls).setUpClass()
         cls.glance_client = openstack_utils.get_glance_session_client(
             cls.keystone_session)
 
     def test_410_glance_image_create_delete(self):
-        """Create an image and then delete it"""
+        """Create an image and then delete it."""
         image_url = openstack_utils.find_cirros_image(arch='x86_64')
         image = openstack_utils.create_image(
             self.glance_client,
@@ -24,8 +27,11 @@ class GlanceTest(test_utils.OpenStackBaseTest):
         openstack_utils.delete_image(self.glance_client, image.id)
 
     def test_411_set_disk_format(self):
-        """Change disk format and assert then change propagates to the correct
-           file and that services are restarted as a result"""
+        """Change disk format and check.
+
+        Change disk format and assert then change propagates to the correct
+        file and that services are restarted as a result
+        """
         # Expected default and alternate values
         set_default = {
             'disk-formats': 'ami,ari,aki,vhd,vmdk,raw,qcow2,vdi,iso,root-tar'}
@@ -47,6 +53,9 @@ class GlanceTest(test_utils.OpenStackBaseTest):
             ['glance-api'])
 
     def test_901_pause_resume(self):
-        """Pause service and check services are stopped then resume and check
-           they are started"""
+        """Run pause and resume tests.
+
+        Pause service and check services are stopped then resume and check
+        they are started
+        """
         self.pause_resume(['glance-api'])
diff --git a/zaza/charm_tests/test_utils.py b/zaza/charm_tests/test_utils.py
index 80860fd..4768ece 100644
--- a/zaza/charm_tests/test_utils.py
+++ b/zaza/charm_tests/test_utils.py
@@ -1,3 +1,4 @@
+"""Module containg base class for implementing charm tests."""
 import logging
 import unittest
 import zaza.model
@@ -8,6 +9,7 @@ import zaza.utilities.openstack as openstack_utils
 
 
 def skipIfNotHA(service_name):
+    """Run decorator to skip tests if application not in HA configuration."""
     def _skipIfNotHA_inner_1(f):
         def _skipIfNotHA_inner_2(*args, **kwargs):
             ips = zaza.model.get_app_ips(
@@ -23,10 +25,11 @@ def skipIfNotHA(service_name):
 
 
 class OpenStackBaseTest(unittest.TestCase):
-    """Generic helpers for testing OpenStack API charms"""
+    """Generic helpers for testing OpenStack API charms."""
 
     @classmethod
     def setUpClass(cls):
+        """Run setup for test class to create common resourcea."""
         cls.keystone_session = openstack_utils.get_overcloud_keystone_session()
         cls.model_name = model.get_juju_model()
         cls.test_config = lifecycle_utils.get_charm_config()
@@ -38,8 +41,10 @@ class OpenStackBaseTest(unittest.TestCase):
 
     def restart_on_changed(self, config_file, default_config, alternate_config,
                            default_entry, alternate_entry, services):
-        """Test that changing config results in config file being updates and
-           services restarted. Return config to default_config afterwards
+        """Run restart on change tests.
+
+        Test that changing config results in config file being updates and
+        services restarted. Return config to default_config afterwards
 
         :param config_file: Config file to check for settings
         :type config_file: str
@@ -114,8 +119,10 @@ class OpenStackBaseTest(unittest.TestCase):
             self.test_config.get('target_deploy_status', {}))
 
     def pause_resume(self, services):
-        """Pause and then resume a unit checking that services are in the
-           required state after each action
+        """Run Pause and resume tests.
+
+        Pause and then resume a unit checking that services are in the
+        required state after each action
 
         :param services: Services expected to be restarted when config_file is
                          changed.
diff --git a/zaza/charm_tests/vault/__init__.py b/zaza/charm_tests/vault/__init__.py
index e69de29..c9c701e 100644
--- a/zaza/charm_tests/vault/__init__.py
+++ b/zaza/charm_tests/vault/__init__.py
@@ -0,0 +1 @@
+"""Collection of code for setting up and testing vault."""
diff --git a/zaza/charm_tests/vault/setup.py b/zaza/charm_tests/vault/setup.py
index 9db4de0..6fe8ce5 100644
--- a/zaza/charm_tests/vault/setup.py
+++ b/zaza/charm_tests/vault/setup.py
@@ -4,6 +4,7 @@ import zaza.charm_tests.vault.utils as vault_utils
 
 
 def basic_setup():
+    """Run basic setup for vault tests."""
     clients = vault_utils.get_clients()
     vip_client = vault_utils.get_vip_client()
     if vip_client:
diff --git a/zaza/charm_tests/vault/tests.py b/zaza/charm_tests/vault/tests.py
index 3b89eca..5307737 100644
--- a/zaza/charm_tests/vault/tests.py
+++ b/zaza/charm_tests/vault/tests.py
@@ -1,4 +1,5 @@
 #!/usr/bin/env python3
+"""Collection of tests for vault."""
 
 import hvac
 import time
@@ -15,9 +16,11 @@ import zaza.model
 
 
 class VaultTest(unittest.TestCase):
+    """Encapsulate vault tests."""
 
     @classmethod
     def setUpClass(cls):
+        """Run setup for Vault tests."""
         cls.clients = vault_utils.get_clients()
         cls.vip_client = vault_utils.get_vip_client()
         if cls.vip_client:
@@ -27,6 +30,7 @@ class VaultTest(unittest.TestCase):
         vault_utils.auth_all(cls.clients, cls.vault_creds['root_token'])
 
     def test_csr(self):
+        """Test generating a csr and uploading a signed certificate."""
         vault_actions = zaza.model.get_actions(
             'vault')
         if 'get-csr' not in vault_actions:
@@ -70,6 +74,7 @@ class VaultTest(unittest.TestCase):
             requests.get('https://{}:5000'.format(ip), verify=fp.name)
 
     def test_all_clients_authenticated(self):
+        """Check all vault clients are authenticated."""
         for client in self.clients:
             for i in range(1, 10):
                 try:
@@ -82,12 +87,14 @@ class VaultTest(unittest.TestCase):
                 self.assertTrue(client.hvac_client.is_authenticated())
 
     def check_read(self, key, value):
+        """Check reading the key from all vault units."""
         for client in self.clients:
             self.assertEqual(
                 client.hvac_client.read('secret/uuids')['data']['uuid'],
                 value)
 
     def test_consistent_read_write(self):
+        """Test reading and writing data to vault."""
         key = 'secret/uuids'
         for client in self.clients:
             value = str(uuid.uuid1())
@@ -97,6 +104,7 @@ class VaultTest(unittest.TestCase):
 
     @test_utils.skipIfNotHA('vault')
     def test_vault_ha_statuses(self):
+        """Check Vault charm HA status."""
         leader = []
         leader_address = []
         leader_cluster_address = []
@@ -116,11 +124,13 @@ class VaultTest(unittest.TestCase):
         self.assertEqual(len(set(leader_cluster_address)), 1)
 
     def test_check_vault_status(self):
+        """Check Vault charm status."""
         for client in self.clients:
             self.assertFalse(client.hvac_client.seal_status['sealed'])
             self.assertTrue(client.hvac_client.seal_status['cluster_name'])
 
     def test_vault_authorize_charm_action(self):
+        """Test the authorize_charm action."""
         vault_actions = zaza.model.get_actions(
             'vault')
         if 'authorize-charm' not in vault_actions:
diff --git a/zaza/charm_tests/vault/utils.py b/zaza/charm_tests/vault/utils.py
index 9666c2b..a1f936b 100644
--- a/zaza/charm_tests/vault/utils.py
+++ b/zaza/charm_tests/vault/utils.py
@@ -1,4 +1,5 @@
 #!/usr/bin/env python3
+"""Module of functions for interfacing with vault and the vault charm."""
 
 import base64
 import hvac
@@ -18,7 +19,7 @@ CharmVaultClient = collections.namedtuple(
 
 
 def get_unit_api_url(ip):
-    """Return URL for api access
+    """Return URL for api access.
 
     :param unit_ip: IP address to use in vault url
     :type unit_ip: str
@@ -29,7 +30,7 @@ def get_unit_api_url(ip):
 
 
 def get_hvac_client(vault_url):
-    """Return an hvac client for the given URL
+    """Return an hvac client for the given URL.
 
     :param vault_url: Vault url to point client at
     :type vault_url: str
@@ -40,7 +41,7 @@ def get_hvac_client(vault_url):
 
 
 def get_vip_client():
-    """Return CharmVaultClient for the vip if a vip is being used
+    """Return CharmVaultClient for the vip if a vip is being used.
 
     :returns: CharmVaultClient
     :rtype: CharmVaultClient or None
@@ -57,7 +58,7 @@ def get_vip_client():
 
 
 def init_vault(client, shares=1, threshold=1):
-    """Initialise vault
+    """Initialise vault.
 
     :param client: Client to use for initiliasation
     :type client: CharmVaultClient
@@ -72,7 +73,7 @@ def init_vault(client, shares=1, threshold=1):
 
 
 def get_clients(units=None):
-    """Create a list of clients, one per vault server
+    """Create a list of clients, one per vault server.
 
     :param units: List of IP addresses of vault endpoints
     :type units: [str, str, ...]
@@ -92,7 +93,7 @@ def get_clients(units=None):
 
 
 def is_initialized(client):
-    """Check if vault is initialized
+    """Check if vault is initialized.
 
     :param client: Client to use to check if vault is initialized
     :type client: CharmVaultClient
@@ -116,8 +117,10 @@ def is_initialized(client):
 
 
 def get_credentails():
-    """Retrieve vault token and keys from unit. These are stored on a unit
-       during functional tests.
+    """Retrieve vault token and keys from unit.
+
+    Retrieve vault token and keys from unit. These are stored on a unit
+    during functional tests.
 
     :returns: Tokens and keys for accessing test environment
     :rtype: dict
@@ -135,8 +138,10 @@ def get_credentails():
 
 
 def store_credentails(creds):
-    """Store the supplied credentials on a vault unit. ONLY USE FOR FUNCTIONAL
-       TESTING.
+    """Store the supplied credentials.
+
+    Store the supplied credentials on a vault unit. ONLY USE FOR FUNCTIONAL
+    TESTING.
 
     :param creds: Keys and token to store
     :type creds: dict
@@ -152,7 +157,7 @@ def store_credentails(creds):
 
 
 def get_credentails_from_file(auth_file):
-    """Read the vault credentials from the auth_file
+    """Read the vault credentials from the auth_file.
 
     :param auth_file: Path to file with credentials
     :type auth_file: str
@@ -165,7 +170,7 @@ def get_credentails_from_file(auth_file):
 
 
 def write_credentails(auth_file, vault_creds):
-    """Write the vault credentials to the auth_file
+    """Write the vault credentials to the auth_file.
 
     :param auth_file: Path to file to write credentials
     :type auth_file: str
@@ -175,7 +180,7 @@ def write_credentails(auth_file, vault_creds):
 
 
 def unseal_all(clients, key):
-    """Unseal all the vaults with the given clients with the provided key
+    """Unseal all the vaults with the given clients with the provided key.
 
     :param clients: List of clients
     :type clients: [CharmVaultClient, ...]
@@ -188,7 +193,7 @@ def unseal_all(clients, key):
 
 
 def auth_all(clients, token):
-    """Authenticate all the given clients with the provided token
+    """Authenticate all the given clients with the provided token.
 
     :param clients: List of clients
     :type clients: [CharmVaultClient, ...]
@@ -200,6 +205,16 @@ def auth_all(clients, token):
 
 
 def run_charm_authorize(token):
+    """Authorize charm to perfom certain actions.
+
+    Run vault charm action to authorize the charm to perform a limited
+    set of calls against the vault API.
+
+    :param token: Token to authorize action against vault.
+    :type token: str
+    :returns: Action object
+    :rtype: juju.action.Action
+    """
     return zaza.model.run_action_on_leader(
         'vault',
         'authorize-charm',
@@ -207,6 +222,13 @@ def run_charm_authorize(token):
 
 
 def run_get_csr():
+    """Retrieve CSR from vault.
+
+    Run vault charm action to retrieve CSR from vault.
+
+    :returns: Action object
+    :rtype: juju.action.Action
+    """
     return zaza.model.run_action_on_leader(
         'vault',
         'get-csr',
@@ -214,6 +236,18 @@ def run_get_csr():
 
 
 def run_upload_signed_csr(pem, root_ca, allowed_domains):
+    """Upload signed cert to vault.
+
+    :param pem: Signed certificate text
+    :type pem: str
+    :param token: Root CA text.
+    :type token: str
+    :param allowed_domains: List of domains that may have certs issued from
+                            certificate.
+    :type allowed_domains: list
+    :returns: Action object
+    :rtype: juju.action.Action
+    """
     return zaza.model.run_action_on_leader(
         'vault',
         'upload-signed-csr',
diff --git a/zaza/configure/__init__.py b/zaza/configure/__init__.py
index e69de29..b36eaa0 100644
--- a/zaza/configure/__init__.py
+++ b/zaza/configure/__init__.py
@@ -0,0 +1 @@
+"""Module for configuring deployed applications."""
diff --git a/zaza/configure/bgp_speaker.py b/zaza/configure/bgp_speaker.py
index 091c0da..f2fcc45 100755
--- a/zaza/configure/bgp_speaker.py
+++ b/zaza/configure/bgp_speaker.py
@@ -1,4 +1,5 @@
 #!/usr/bin/env python3
+"""Module to setup BGP speaker configuration."""
 
 import argparse
 import logging
@@ -16,7 +17,7 @@ FIP_TEST = "FIP TEST"
 
 
 def setup_bgp_speaker(peer_application_name, keystone_session=None):
-    """Setup BGP Speaker
+    """Perform BGP Speaker setup.
 
     :param peer_application_name: String name of BGP peer application
     :type peer_application_name: string
@@ -84,12 +85,11 @@ def setup_bgp_speaker(peer_application_name, keystone_session=None):
 
 
 def run_from_cli():
-    """Run BGP Speaker setup from CLI
+    """Run BGP Speaker setup from CLI.
 
     :returns: None
     :rtype: None
     """
-
     cli_utils.setup_logging()
     parser = argparse.ArgumentParser()
     parser.add_argument("--peer-application", "-a",
diff --git a/zaza/configure/network.py b/zaza/configure/network.py
index 8dc3e13..f461ca1 100755
--- a/zaza/configure/network.py
+++ b/zaza/configure/network.py
@@ -1,17 +1,6 @@
 #!/usr/bin/env python3
 
-import argparse
-import logging
-import sys
-
-from zaza.utilities import (
-    cli as cli_utils,
-    generic as generic_utils,
-    juju as juju_utils,
-    openstack as openstack_utils,
-)
-
-"""Configure network
+"""Configure network.
 
 For these network configuration functions there are two distinct sets of
 settings. There is the configuration of the overcloud's network, the network
@@ -75,9 +64,20 @@ As a script from CLI with a YAML file of configuration:
     ./network toploogy_name -f network.yaml
 """
 
+import argparse
+import logging
+import sys
+
+from zaza.utilities import (
+    cli as cli_utils,
+    generic as generic_utils,
+    juju as juju_utils,
+    openstack as openstack_utils,
+)
+
 
 def setup_sdn(network_config, keystone_session=None):
-    """Setup Software Defined Network
+    """Perform setup for Software Defined Network.
 
     :param network_config: Network configuration settings dictionary
     :type network_config: dict
@@ -86,7 +86,6 @@ def setup_sdn(network_config, keystone_session=None):
     :returns: None
     :rtype: None
     """
-
     # If a session has not been provided, acquire one
     if not keystone_session:
         keystone_session = openstack_utils.get_overcloud_keystone_session()
@@ -168,8 +167,9 @@ def setup_sdn(network_config, keystone_session=None):
 
 
 def setup_gateway_ext_port(network_config, keystone_session=None):
-    """Setup external port on Neutron Gateway.
-    For OpenStack on OpenStack scenarios
+    """Perform setup external port on Neutron Gateway.
+
+    For OpenStack on OpenStack scenarios.
 
     :param network_config: Network configuration dictionary
     :type network_config: dict
@@ -178,7 +178,6 @@ def setup_gateway_ext_port(network_config, keystone_session=None):
     :returns: None
     :rtype: None
     """
-
     # If a session has not been provided, acquire one
     if not keystone_session:
         keystone_session = openstack_utils.get_undercloud_keystone_session()
@@ -204,7 +203,7 @@ def setup_gateway_ext_port(network_config, keystone_session=None):
 
 
 def run_from_cli(**kwargs):
-    """Run network configurations from CLI
+    """Run network configurations from CLI.
 
     Use a YAML file of network configuration settings to configure the
     overcloud network. YAML file of the form:
@@ -225,7 +224,6 @@ def run_from_cli(**kwargs):
     :returns: None
     :rtype: None
     """
-
     cli_utils.setup_logging()
     parser = argparse.ArgumentParser()
     parser.add_argument("net_topology",
diff --git a/zaza/controller.py b/zaza/controller.py
index 928a56d..748c97c 100644
--- a/zaza/controller.py
+++ b/zaza/controller.py
@@ -1,15 +1,18 @@
+"""Module for interacting with a juju controller."""
+
 import logging
 from juju.controller import Controller
 from zaza import sync_wrapper
 
 
 async def async_add_model(model_name, config=None):
-    """Add a model to the current controller
+    """Add a model to the current controller.
 
     :param model_name: Name to give the new model.
     :type model_name: str
     :param config: Model configuration.
-    :type config: dict"""
+    :type config: dict
+    """
     controller = Controller()
     await controller.connect()
     logging.debug("Adding model {}".format(model_name))
@@ -24,10 +27,11 @@ add_model = sync_wrapper(async_add_model)
 
 
 async def async_destroy_model(model_name):
-    """Remove a model from the current controller
+    """Remove a model from the current controller.
 
     :param model_name: Name of model to remove
-    :type model_name: str"""
+    :type model_name: str
+    """
     controller = Controller()
     await controller.connect()
     logging.debug("Destroying model {}".format(model_name))
@@ -38,7 +42,7 @@ destroy_model = sync_wrapper(async_destroy_model)
 
 
 async def async_get_cloud():
-    """Return the name of the current cloud
+    """Return the name of the current cloud.
 
     :returns: Name of cloud
     :rtype: str
@@ -53,7 +57,7 @@ get_cloud = sync_wrapper(async_get_cloud)
 
 
 async def async_list_models():
-    """Return a list of tha available clouds
+    """Return a list of tha available clouds.
 
     :returns: List of clouds
     :rtype: list