diff --git a/src/testdir/test_quickfix.vim b/src/testdir/test_quickfix.vim
index 12bfe32..f12f4f2 100644
--- a/src/testdir/test_quickfix.vim
+++ b/src/testdir/test_quickfix.vim
@@ -1795,6 +1795,9 @@
     call assert_equal(0, s)
     let d = g:Xgetlist({"title":1})
     call assert_equal('Sample', d.title)
+    " Try setting title to a non-string value
+    call assert_equal(-1, g:Xsetlist([], 'a', {'title' : ['Test']}))
+    call assert_equal('Sample', g:Xgetlist({"title":1}).title)
 
     Xopen
     call assert_equal('Sample', w:quickfix_title)
@@ -1943,6 +1946,9 @@
     call g:Xsetlist([], 'a', {'items' : [{'filename':'F1', 'lnum':10}]})
     call assert_equal(10, g:Xgetlist({'items':1}).items[0].lnum)
 
+    " Try setting the items using a string
+    call assert_equal(-1, g:Xsetlist([], ' ', {'items' : 'Test'}))
+
     " Save and restore the quickfix stack
     call g:Xsetlist([], 'f')
     call assert_equal(0, g:Xgetlist({'nr':'$'}).nr)