diff --git a/src/testdir/test_substitute.vim b/src/testdir/test_substitute.vim
index 7c2bbb4..cf2c73f 100644
--- a/src/testdir/test_substitute.vim
+++ b/src/testdir/test_substitute.vim
@@ -1498,4 +1498,18 @@
   exe bufnr .. "bw!"
 endfunc
 
+" Test for changing 'cpo' in a substitute expression
+func Test_substitute_expr_cpo()
+  func XSubExpr()
+    set cpo=
+    return 'x'
+  endfunc
+
+  let save_cpo = &cpo
+  call assert_equal('xxx', substitute('abc', '.', '\=XSubExpr()', 'g'))
+  call assert_equal(save_cpo, &cpo)
+
+  delfunc XSubExpr
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab