diff --git a/lld/test/pecoff/Inputs/responsefile.txt b/lld/test/pecoff/Inputs/responsefile.txt
index c91f4d03485c..08286119d4ed 100644
--- a/lld/test/pecoff/Inputs/responsefile.txt
+++ b/lld/test/pecoff/Inputs/responsefile.txt
@@ -1 +1 @@
--foo
+-foo -bar\baz
diff --git a/lld/test/pecoff/responsefile.test b/lld/test/pecoff/responsefile.test
index 3ae0ac2512d1..9732cb37d0e0 100644
--- a/lld/test/pecoff/responsefile.test
+++ b/lld/test/pecoff/responsefile.test
@@ -3,3 +3,4 @@
 # RUN: FileCheck %s < %t.log
 
 CHECK: warning: ignoring unknown argument: -foo
+CHECK: warning: ignoring unknown argument: -bar\baz