diff --git a/tests/helpers.lua b/tests/helpers.lua
index 37ef032c..2a0a4b2c 100644
--- a/tests/helpers.lua
+++ b/tests/helpers.lua
@@ -8,10 +8,12 @@ vim.print({
   is_github_action = is_github_action,
 })
 
+--- @return any # given arguments.
 M.debug = function(...)
   if debug_enabled then
-    vim.print(...)
+    return vim.print(...)
   end
+  return {}
 end
 
 M.setup_backport = function()
diff --git a/tests/kitty-scrollback/kitty_scrollback_spec.lua b/tests/kitty-scrollback/kitty_scrollback_spec.lua
index f7375fe3..5522e06c 100644
--- a/tests/kitty-scrollback/kitty_scrollback_spec.lua
+++ b/tests/kitty-scrollback/kitty_scrollback_spec.lua
@@ -10,8 +10,10 @@ local ksb_dir = vim.fn.fnamemodify(
   vim.fn.fnamemodify(vim.api.nvim_get_runtime_file('lua/kitty-scrollback', false)[1], ':h:h'),
   ':p'
 )
-h.debug('ksb_dir: ' .. ksb_dir)
-h.debug(ksb_dir .. 'tests/minimal_kitty.conf')
+h.debug({
+  ksb_dir = ksb_dir,
+  minimal_kitty_conf = ksb_dir .. 'tests/minimal_kitty.conf',
+})
 
 local tmpsock = h.tempsocket(ksb_dir .. 'tmp/')
 local kitty_instance