diff --git a/oslo_rootwrap/filters.py b/oslo_rootwrap/filters.py
index c4c7abc..ba017af 100644
--- a/oslo_rootwrap/filters.py
+++ b/oslo_rootwrap/filters.py
@@ -325,8 +325,8 @@ class EnvFilter(CommandFilter):
         user_command = userargs[len(user_envs):len(user_envs) + 1]
 
         # match first non-env argument with CommandFilter
-        return (super(EnvFilter, self).match(user_command)
-                and len(filter_envs) and user_envs == filter_envs)
+        return (super(EnvFilter, self).match(user_command) and
+                len(filter_envs) and user_envs == filter_envs)
 
     def exec_args(self, userargs):
         args = userargs[:]
@@ -377,8 +377,8 @@ class IpNetnsExecFilter(ChainingFilter):
         if self.run_as != "root" or len(userargs) < 4:
             return False
 
-        return (userargs[0] == 'ip' and userargs[1] in NETNS_VARS
-                and userargs[2] in EXEC_VARS)
+        return (userargs[0] == 'ip' and userargs[1] in NETNS_VARS and
+                userargs[2] in EXEC_VARS)
 
     def exec_args(self, userargs):
         args = userargs[4:]
diff --git a/oslo_rootwrap/wrapper.py b/oslo_rootwrap/wrapper.py
index 0e115f8..c454fe2 100644
--- a/oslo_rootwrap/wrapper.py
+++ b/oslo_rootwrap/wrapper.py
@@ -19,15 +19,15 @@ import os
 import signal
 import sys
 
-if sys.platform != 'win32':
-    import pwd
-
 import six
 from six import moves
 
 from oslo_rootwrap import filters
 from oslo_rootwrap import subprocess
 
+if sys.platform != 'win32':
+    import pwd
+
 
 class NoFilterMatched(Exception):
     """This exception is raised when no filter matched."""
@@ -73,8 +73,8 @@ class RootwrapConfig(object):
         if config.has_option("DEFAULT", "syslog_log_level"):
             v = config.get("DEFAULT", "syslog_log_level")
             level = v.upper()
-            if (hasattr(logging, '_nameToLevel')
-               and level in logging._nameToLevel):
+            if (hasattr(logging, '_nameToLevel') and
+               level in logging._nameToLevel):
                 # Workaround a regression of Python 3.4.0 bug fixed in 3.4.2:
                 # http://bugs.python.org/issue22386
                 self.syslog_log_level = logging._nameToLevel[level]
@@ -177,8 +177,8 @@ def match_filter(filter_list, userargs, exec_dirs=None):
                 # This command calls exec verify that remaining args
                 # matches another filter.
                 def non_chain_filter(fltr):
-                    return (fltr.run_as == f.run_as
-                            and not isinstance(fltr, filters.ChainingFilter))
+                    return (fltr.run_as == f.run_as and
+                            not isinstance(fltr, filters.ChainingFilter))
 
                 leaf_filters = [fltr for fltr in filter_list
                                 if non_chain_filter(fltr)]
diff --git a/test-requirements.txt b/test-requirements.txt
index ed60fb1..b2c4e8f 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -2,7 +2,7 @@
 # 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
 
 fixtures>=3.0.0 # Apache-2.0/BSD
 testtools>=2.2.0 # MIT
diff --git a/tox.ini b/tox.ini
index 0ed64d5..894d265 100644
--- a/tox.ini
+++ b/tox.ini
@@ -49,7 +49,10 @@ deps = -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -W -b html doc/source doc/build/html
 
 [flake8]
+# E731 skipped as assign a lambda expression
+
 show-source = True
+ignore = E731
 exclude = .tox,dist,doc,*.egg,build
 
 [testenv:benchmark]