diff --git a/src/testdir/test_clientserver.vim b/src/testdir/test_clientserver.vim
index 7936227..4a48aed 100644
--- a/src/testdir/test_clientserver.vim
+++ b/src/testdir/test_clientserver.vim
@@ -129,7 +129,7 @@
 
     " Edit files in separate tab pages
     call system(cmd .. ' --remote-tab Xfile1 Xfile2 Xfile3')
-    call assert_equal('3', remote_expr(name, 'tabpagenr("$")'))
+    call WaitForAssert({-> assert_equal('3', remote_expr(name, 'tabpagenr("$")'))})
     call assert_equal('Xfile2', remote_expr(name, 'bufname(tabpagebuflist(2)[0])'))
     eval name->remote_send(":%bw!\<CR>")