diff --git a/tests/xargs_test.py b/tests/xargs_test.py
index de16a012..65336c58 100644
--- a/tests/xargs_test.py
+++ b/tests/xargs_test.py
@@ -55,7 +55,8 @@ def test_partition_limits():
 
 def test_partition_limit_win32(sys_win32_mock):
     cmd = ('ninechars',)
-    varargs = ('😑' * 10,)
+    # counted as half because of utf-16 encode
+    varargs = ('😑' * 5,)
     with mock.patch('pre_commit.xargs.sys', sys_win32_mock):
         ret = xargs.partition(cmd, varargs, _max_length=20)