diff --git a/tests/shell.py b/tests/shell.py
index df12a1cd..41a8be0f 100644
--- a/tests/shell.py
+++ b/tests/shell.py
@@ -124,8 +124,10 @@ def msize(path):
         w.write('0')
     os.utime(path, (0, 0))
 
+
 def mount_tmpfs(path):
     os.system(f'mount -t tmpfs none {path}')
 
+
 def unmount(path):
     os.system(f'umount {path}')