diff --git a/test-requirements.txt b/test-requirements.txt
index 52d6366e..ae4d8b59 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -5,3 +5,5 @@ jsonschema
 Sphinx
 sphinxcontrib.datatemplates
 refstack>=2.0.0
+hacking>=1.1.0,!=1.2.0 # Apache-2.0
+flake8!=3.0.0,!=2.6.2 # MIT
diff --git a/tools/checktests.py b/tools/checktests.py
index 6b148788..eeac86a3 100644
--- a/tools/checktests.py
+++ b/tools/checktests.py
@@ -12,8 +12,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import ast
 import argparse
+import ast
 import importlib
 import json
 import os
diff --git a/tox.ini b/tox.ini
index 0fd58c5c..66bdeb92 100644
--- a/tox.ini
+++ b/tox.ini
@@ -24,9 +24,7 @@ commands=
 
 [testenv:pep8]
 ignore = W504
-deps =
-  flake8
-  {[testenv]deps}
+deps = {[testenv]deps}
 commands=
   bash tools/flake8wrap.sh
   doc8 -e .rst doc/source
diff --git a/working_materials/tabulate_scores.py b/working_materials/tabulate_scores.py
index 26d59496..c0578b68 100755
--- a/working_materials/tabulate_scores.py
+++ b/working_materials/tabulate_scores.py
@@ -14,9 +14,9 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import re
-import json
 import argparse
+import json
+import re
 import textwrap