diff --git a/ironic/tests/unit/common/test_images.py b/ironic/tests/unit/common/test_images.py
index 44975e16ef..59c5f3f01a 100644
--- a/ironic/tests/unit/common/test_images.py
+++ b/ironic/tests/unit/common/test_images.py
@@ -261,7 +261,8 @@ class FsImageTestCase(base.TestCase):
     def test__create_root_fs(self, path_exists_mock,
                              dirname_mock, mkdir_mock, cp_mock):
 
-        path_exists_mock_func = lambda path: path == 'root_dir'
+        def path_exists_mock_func(path):
+            return path == 'root_dir'
 
         files_info = {
             'a1': 'b1',
diff --git a/test-requirements.txt b/test-requirements.txt
index c2b419e35f..7bc314665c 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -28,4 +28,3 @@ sphinxcontrib-seqdiag # BSD
 openstackdocstheme>=1.16.0 # Apache-2.0
 reno!=2.3.1,>=1.8.0 # Apache-2.0
 os-api-ref>=1.0.0 # Apache-2.0
-pycodestyle<=2.3.1
diff --git a/tox.ini b/tox.ini
index a2603276b7..50e8b3a5c7 100644
--- a/tox.ini
+++ b/tox.ini
@@ -95,7 +95,9 @@ setenv = PYTHONHASHSEED=0
 commands = {posargs}
 
 [flake8]
-ignore = E129
+# [E402] Module level import not at top of file
+# [W503] Line break before binary operator.
+ignore = E129,E402,W503
 exclude =  .venv,.git,.tox,dist,doc,*lib/python*,*egg,build
 import-order-style = pep8
 application-import-names = ironic