diff --git a/test-requirements.txt b/test-requirements.txt
index 83c362b..34e0469 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,7 +1,7 @@
 # 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.
-hacking!=0.13.0,<0.14,>=0.12.0 # Apache-2.0
+hacking>=1.1.0,<1.2.0 # Apache-2.0
 stestr>=2.0.0 # Apache-2.0
 
 sphinx!=1.6.6,!=1.6.7,>=1.6.5 # BSD
diff --git a/tox.ini b/tox.ini
index 7bc6a66..934fb13 100644
--- a/tox.ini
+++ b/tox.ini
@@ -43,9 +43,10 @@ commands =
 
 [flake8]
 # E123, E125 skipped as they are invalid PEP-8.
+# E731 skipped as assign a lambda expression
 
 show-source = True
-ignore = E123,E125
+ignore = E123,E125,E731
 
 # H106: Don’t put vim configuration in source files
 # H203: Use assertIs(Not)None to check for None