--- a/testing/remotecppunittests.py
+++ b/testing/remotecppunittests.py
@@ -175,17 +175,18 @@ class RemoteCPPUnittestOptions(cppunitte
 
         self.add_option("--devicePort", action="store",
                         type="string", dest="device_port",
                         help="port of remote device to test")
         defaults["device_port"] = 20701
 
         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",
                         type="string", dest="local_lib",
                         help="location of libraries to push -- preferably stripped")
         defaults["local_lib"] = None
 
         self.add_option("--apk", action="store",
@@ -208,17 +209,18 @@ class RemoteCPPUnittestOptions(cppunitte
 
         self.add_option("--with-b2g-emulator", action="store",
                         type="string", dest="with_b2g_emulator",
                         help="Start B2G Emulator (specify path to b2g home)")
         self.add_option("--emulator", default="arm", choices=["x86", "arm"],
                         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)
 
 
 def run_test_harness(options, args):
     if options.with_b2g_emulator:
         from mozrunner import B2GEmulatorRunner
@@ -232,17 +234,17 @@ def run_test_harness(options, args):
         retryLimit = 5
     try:
         dm_args = {'deviceRoot': options.remote_test_root}
         dm_args['retryLimit'] = retryLimit
         if options.device_ip:
             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:
             runner.cleanup()
             runner.wait()
         raise
 
     options.xre_path = os.path.abspath(options.xre_path)

--- a/testing/runcppunittests.py
+++ b/testing/runcppunittests.py
@@ -90,17 +90,18 @@ class CPPUnitTests(object):
         env["XPCOM_DEBUG_BREAK"] = "stack-and-abort"
         env["MOZ_CRASHREPORTER_NO_REPORT"] = "1"
         env["MOZ_CRASHREPORTER"] = "1"
         return env
 
     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)
         env = dict(os.environ)
         env = self.build_core_environment(env)
         pathvar = ""
         libpath = self.xre_path
         if mozinfo.os == "linux":
@@ -180,17 +181,18 @@ class CPPUnittestOptions(OptionParser):
         OptionParser.__init__(self)
         self.add_option("--xre-path",
                         action="store", type="string", dest="xre_path",
                         default=None,
                         help="absolute path to directory containing XRE (probably xulrunner)")
         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,
                         help="path to test manifest, if different from the path to test binaries")
 
 
 def extract_unittests_from_args(args, environ, manifest_path):
     """Extract unittests from args, expanding directories as needed"""
@@ -213,19 +215,26 @@ def extract_unittests_from_args(args, en
             else:
                 tests.append((os.path.abspath(p), 1))
 
     # we skip the existence check here because not all tests are built
     # for all platforms (and it will fail on Windows anyway)
     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])]
 
     return tests
 
 
 def update_mozinfo():

--- a/tools/lint/flake8.yml
+++ b/tools/lint/flake8.yml
@@ -12,16 +12,18 @@ flake8:
         - taskcluster
         - testing/firefox-ui
         - testing/mach_commands.py
         - testing/marionette/client
         - testing/marionette/harness
         - testing/marionette/puppeteer
         - testing/mozbase
         - testing/mochitest
+        - testing/remotecppunittests.py
+        - testing/runcppunittests.py
         - testing/talos/
         - testing/xpcshell
         - tools/git
         - tools/lint
         - tools/mercurial
         - tools/tryselect
         - toolkit/components/telemetry
     # Excludes should be added to topsrcdir/.flake8 due to a bug in flake8 where