diff --git a/src/testdir/test_compiler.vim b/src/testdir/test_compiler.vim
index 46c14d8..f561e84 100644
--- a/src/testdir/test_compiler.vim
+++ b/src/testdir/test_compiler.vim
@@ -10,6 +10,10 @@
     unlet $LANG
   endif
 
+  " %:S does not work properly with 'shellslash' set
+  let save_shellslash = &shellslash
+  set noshellslash
+
   e Xfoo.pl
   compiler perl
   call assert_equal('perl', b:current_compiler)
@@ -27,6 +31,7 @@
   call assert_match("\n 1 Xfoo.pl:3: Global symbol \"\$foo\" "
   \ .               "requires explicit package name", a)
 
+  let &shellslash = save_shellslash
   call delete('Xfoo.pl')
   bw!
 endfunc