diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index 427e404..2cf9006 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -450,7 +450,7 @@
   call assert_equal('/',           simplify('/.'))
   call assert_equal('/',           simplify('/..'))
   call assert_equal('/...',        simplify('/...'))
-  call assert_equal('./dir/file',  simplify('./dir/file'))
+  call assert_equal('./dir/file',  './dir/file'->simplify())
   call assert_equal('./dir/file',  simplify('.///dir//file'))
   call assert_equal('./dir/file',  simplify('./dir/./file'))
   call assert_equal('./file',      simplify('./dir/../file'))