diff --git a/testing/remotecppunittests.py b/testing/remotecppunittests.py
index fbe2f5335c1f..80af905f34dc 100644
--- a/testing/remotecppunittests.py
+++ b/testing/remotecppunittests.py
@@ -180,7 +180,8 @@ class RemoteCPPUnittestOptions(cppunittests.CPPUnittestOptions):
 
         self.add_option("--noSetup", action="store_false",
                         dest="setup",
-                        help="do not copy any files to device (to be used only if device is already setup)")
+                        help="do not copy any files to device (to be used only if "
+                        "device is already setup)")
         defaults["setup"] = True
 
         self.add_option("--localLib", action="store",
@@ -213,7 +214,8 @@ class RemoteCPPUnittestOptions(cppunittests.CPPUnittestOptions):
                         help="Architecture of emulator to use: x86 or arm")
         self.add_option("--addEnv", action="append",
                         type="string", dest="add_env",
-                        help="additional remote environment variable definitions (eg. --addEnv \"somevar=something\")")
+                        help="additional remote environment variable definitions "
+                        "(eg. --addEnv \"somevar=something\")")
         defaults["add_env"] = None
 
         self.set_defaults(**defaults)
@@ -237,7 +239,7 @@ def run_test_harness(options, args):
             dm_args['host'] = options.device_ip
             dm_args['port'] = options.device_port
         if options.log_tbpl_level == 'debug' or options.log_mach_level == 'debug':
-            dm_args['logLevel'] = logging.DEBUG
+            dm_args['logLevel'] = logging.DEBUG # noqa python 2 / 3
         dm = devicemanagerADB.DeviceManagerADB(**dm_args)
     except:
         if options.with_b2g_emulator:
diff --git a/testing/runcppunittests.py b/testing/runcppunittests.py
index f56b5f410c60..a7ba1c925695 100755
--- a/testing/runcppunittests.py
+++ b/testing/runcppunittests.py
@@ -95,7 +95,8 @@ class CPPUnitTests(object):
     def build_environment(self):
         """
         Create and return a dictionary of all the appropriate env variables and values.
-        On a remote system, we overload this to set different values and are missing things like os.environ and PATH.
+        On a remote system, we overload this to set different values and are missing things
+        like os.environ and PATH.
         """
         if not os.path.isdir(self.xre_path):
             raise Exception("xre_path does not exist: %s", self.xre_path)
@@ -185,7 +186,8 @@ class CPPUnittestOptions(OptionParser):
         self.add_option("--symbols-path",
                         action="store", type="string", dest="symbols_path",
                         default=None,
-                        help="absolute path to directory containing breakpad symbols, or the URL of a zip file containing symbols")
+                        help="absolute path to directory containing breakpad symbols, or "
+                        "the URL of a zip file containing symbols")
         self.add_option("--manifest-path",
                         action="store", type="string", dest="manifest_path",
                         default=None,
@@ -218,9 +220,16 @@ def extract_unittests_from_args(args, environ, manifest_path):
     active_tests = mp.active_tests(exists=False, disabled=False, **environ)
     suffix = '.exe' if mozinfo.isWin else ''
     if binary_path:
-        tests.extend([(os.path.join(binary_path, test['relpath'] + suffix), int(test.get('requesttimeoutfactor', 1))) for test in active_tests])
+        tests.extend([
+            (os.path.join(binary_path, test['relpath'] + suffix),
+             int(test.get('requesttimeoutfactor', 1)))
+            for test in active_tests])
     else:
-        tests.extend([(test['path'] + suffix, int(test.get('requesttimeoutfactor', 1))) for test in active_tests])
+        tests.extend([
+            (test['path'] + suffix,
+             int(test.get('requesttimeoutfactor', 1)))
+            for test in active_tests
+        ])
 
     # skip non-existing tests
     tests = [test for test in tests if os.path.isfile(test[0])]
diff --git a/tools/lint/flake8.yml b/tools/lint/flake8.yml
index 7c787abbc7fb..fed7d53b497e 100644
--- a/tools/lint/flake8.yml
+++ b/tools/lint/flake8.yml
@@ -17,6 +17,8 @@ flake8:
         - testing/marionette/puppeteer
         - testing/mozbase
         - testing/mochitest
+        - testing/remotecppunittests.py
+        - testing/runcppunittests.py
         - testing/talos/
         - testing/xpcshell
         - tools/git