diff --git a/src/lib/charm/openstack/designate.py b/src/lib/charm/openstack/designate.py
index a8be2b8..a6127a5 100644
--- a/src/lib/charm/openstack/designate.py
+++ b/src/lib/charm/openstack/designate.py
@@ -270,7 +270,7 @@ class BindRNDCRelationAdapter(openstack_adapters.OpenStackRelationAdapter):
 
 
 class DesignateConfigurationAdapter(
-      openstack_adapters.APIConfigurationAdapter):
+        openstack_adapters.APIConfigurationAdapter):
 
     def __init__(self, port_map=None):
         super(DesignateConfigurationAdapter, self).__init__(
diff --git a/src/tox.ini b/src/tox.ini
index 4a6291e..479d7bb 100644
--- a/src/tox.ini
+++ b/src/tox.ini
@@ -1,13 +1,16 @@
+# Source charm: ./src/tox.ini
+# This file is managed centrally by release-tools and should not be modified
+# within individual charm repos.
 [tox]
 envlist = pep8
 skipsdist = True
 
 [testenv]
-envdir = .tox/py27
 setenv = VIRTUAL_ENV={envdir}
          PYTHONHASHSEED=0
          AMULET_SETUP_TIMEOUT=2700
-passenv = HOME TERM AMULET_HTTP_PROXY AMULET_OS_VIP
+whitelist_externals = juju
+passenv = HOME TERM AMULET_*
 deps = -r{toxinidir}/test-requirements.txt
 install_command =
   pip install --allow-unverified python-apt {opts} {packages}
@@ -23,28 +26,24 @@ commands =
     bundletester -vl DEBUG -r json -o func-results.json --test-pattern "gate-*" -n --no-destroy
 
 [testenv:func27]
-# Charm Functional Test
 # Run all gate tests which are +x (expected to always pass)
 basepython = python2.7
 commands =
     bundletester -vl DEBUG -r json -o func-results.json --test-pattern "gate-*" --no-destroy
 
 [testenv:func27-smoke]
-# Charm Functional Test
 # Run a specific test as an Amulet smoke test (expected to always pass)
 basepython = python2.7
 commands =
     bundletester -vl DEBUG -r json -o func-results.json gate-basic-xenial-mitaka --no-destroy
 
 [testenv:func27-dfs]
-# Charm Functional Test
 # Run all deploy-from-source tests which are +x (may not always pass!)
 basepython = python2.7
 commands =
     bundletester -vl DEBUG -r json -o func-results.json --test-pattern "dfs-*" --no-destroy
 
 [testenv:func27-dev]
-# Charm Functional Test
 # Run all development test targets which are +x (may not always pass!)
 basepython = python2.7
 commands =
diff --git a/tox.ini b/tox.ini
index 26da278..893f30f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,36 +1,28 @@
+# Source charm: ./tox.ini
+# This file is managed centrally by release-tools and should not be modified
+# within individual charm repos.
 [tox]
 skipsdist = True
 envlist = pep8,py34,py35
 skip_missing_interpreters = True
 
 [testenv]
-basepython = python2.7
 setenv = VIRTUAL_ENV={envdir}
          PYTHONHASHSEED=0
          TERM=linux
-         INTERFACE_PATH={toxinidir}/interfaces
          LAYER_PATH={toxinidir}/layers
+         INTERFACE_PATH={toxinidir}/interfaces
          JUJU_REPOSITORY={toxinidir}/build
 passenv = http_proxy https_proxy
 install_command =
   pip install {opts} {packages}
 deps =
-  -r{toxinidir}/requirements.txt
+    -r{toxinidir}/requirements.txt
 
 [testenv:build]
+basepython = python2.7
 commands =
-  charm-build --log-level DEBUG -o {toxinidir}/build src
-
-[testenv:venv]
-commands = {posargs}
-
-[testenv:pep8]
-commands = flake8 {posargs} src/reactive src/lib unit_tests
-
-# Disable py27 tests as this is a reactive python 3 charm. Once project
-# config has been updated this tox target can be removed
-[testenv:py27]
-commands = /bin/true
+    charm-build --log-level DEBUG -o {toxinidir}/build src {posargs}
 
 [testenv:py34]
 basepython = python3.4
@@ -41,3 +33,15 @@ commands = ostestr {posargs}
 basepython = python3.5
 deps = -r{toxinidir}/test-requirements.txt
 commands = ostestr {posargs}
+
+[testenv:pep8]
+basepython = python2.7
+deps = -r{toxinidir}/test-requirements.txt
+commands = flake8 {posargs} src unit_tests
+
+[testenv:venv]
+commands = {posargs}
+
+[flake8]
+# E402 ignore necessary for path append before sys module import in actions
+ignore = E402