--- a/tests/fsmonitor-run-tests.py	Sat Oct 05 10:29:34 2019 -0400
+++ b/tests/fsmonitor-run-tests.py	Sun Oct 06 09:45:02 2019 -0400
@@ -28,14 +28,18 @@
 
 if sys.version_info > (3, 5, 0):
     PYTHON3 = True
-    xrange = range # we use xrange in one place, and we'd rather not use range
+    xrange = range  # we use xrange in one place, and we'd rather not use range
+
     def _bytespath(p):
         return p.encode('utf-8')
 
+
 elif sys.version_info >= (3, 0, 0):
-    print('%s is only supported on Python 3.5+ and 2.7, not %s' %
-          (sys.argv[0], '.'.join(str(v) for v in sys.version_info[:3])))
-    sys.exit(70) # EX_SOFTWARE from `man 3 sysexit`
+    print(
+        '%s is only supported on Python 3.5+ and 2.7, not %s'
+        % (sys.argv[0], '.'.join(str(v) for v in sys.version_info[:3]))
+    )
+    sys.exit(70)  # EX_SOFTWARE from `man 3 sysexit`
 else:
     PYTHON3 = False
 
@@ -46,21 +50,29 @@
     def _bytespath(p):
         return p
 
+
 def getparser():
     """Obtain the argument parser used by the CLI."""
     parser = argparse.ArgumentParser(
         description='Run tests with fsmonitor enabled.',
-        epilog='Unrecognized options are passed to run-tests.py.')
+        epilog='Unrecognized options are passed to run-tests.py.',
+    )
     # - keep these sorted
     # - none of these options should conflict with any in run-tests.py
-    parser.add_argument('--keep-fsmonitor-tmpdir', action='store_true',
-        help='keep temporary directory with fsmonitor state')
-    parser.add_argument('--watchman',
+    parser.add_argument(
+        '--keep-fsmonitor-tmpdir',
+        action='store_true',
+        help='keep temporary directory with fsmonitor state',
+    )
+    parser.add_argument(
+        '--watchman',
         help='location of watchman binary (default: watchman in PATH)',
-        default='watchman')
+        default='watchman',
+    )
 
     return parser
 
+
 @contextlib.contextmanager
 def watchman(args):
     basedir = tempfile.mkdtemp(prefix='hg-fsmonitor')
@@ -82,19 +94,24 @@
 
         argv = [
             args.watchman,
-            '--sockname', sockfile,
-            '--logfile', logfile,
-            '--pidfile', pidfile,
-            '--statefile', statefile,
+            '--sockname',
+            sockfile,
+            '--logfile',
+            logfile,
+            '--pidfile',
+            pidfile,
+            '--statefile',
+            statefile,
             '--foreground',
-            '--log-level=2', # debug logging for watchman
+            '--log-level=2',  # debug logging for watchman
         ]
 
         envb = osenvironb.copy()
         envb[b'WATCHMAN_CONFIG_FILE'] = _bytespath(cfgfile)
         with open(clilogfile, 'wb') as f:
             proc = subprocess.Popen(
-                argv, env=envb, stdin=None, stdout=f, stderr=f)
+                argv, env=envb, stdin=None, stdout=f, stderr=f
+            )
             try:
                 yield sockfile
             finally:
@@ -106,6 +123,7 @@
         else:
             shutil.rmtree(basedir, ignore_errors=True)
 
+
 def run():
     parser = getparser()
     args, runtestsargv = parser.parse_known_args()
@@ -120,20 +138,23 @@
         blacklist = os.path.join(runtestdir, 'blacklists', 'fsmonitor')
 
         runtestsargv.insert(0, runtests)
-        runtestsargv.extend([
-            '--extra-config',
-            'extensions.fsmonitor=',
-            # specify fsmonitor.mode=paranoid always in order to force
-            # fsmonitor extension execute "paranoid" code path
-            #
-            # TODO: make fsmonitor-run-tests.py accept specific options
-            '--extra-config',
-            'fsmonitor.mode=paranoid',
-            '--blacklist',
-            blacklist,
-        ])
+        runtestsargv.extend(
+            [
+                '--extra-config',
+                'extensions.fsmonitor=',
+                # specify fsmonitor.mode=paranoid always in order to force
+                # fsmonitor extension execute "paranoid" code path
+                #
+                # TODO: make fsmonitor-run-tests.py accept specific options
+                '--extra-config',
+                'fsmonitor.mode=paranoid',
+                '--blacklist',
+                blacklist,
+            ]
+        )
 
         return subprocess.call(runtestsargv)
 
+
 if __name__ == '__main__':
     sys.exit(run())