2 files changed, 37 insertions, 0 deletions
diff --git a/test/functional/legacy/cmdline_spec.lua b/test/functional/legacy/cmdline_spec.lua
index bf146e1322..3addcb957c 100644
--- a/test/functional/legacy/cmdline_spec.lua
+++ b/test/functional/legacy/cmdline_spec.lua
@@ -216,6 +216,22 @@ describe('cmdline', function()
                 longish   |
     ]]
   end)
+
+  -- oldtest: Test_rulerformat_function()
+  it("'rulerformat' can use %!", function()
+    local screen = Screen.new(40, 2)
+    exec([[
+      func TestRulerFn()
+        return '10,20%=30%%'
+      endfunc
+    ]])
+    api.nvim_set_option_value('ruler', true, {})
+    api.nvim_set_option_value('rulerformat', '%!TestRulerFn()', {})
+    screen:expect([[
+      ^                                        |
+                            10,20         30% |
+    ]])
+  end)
 end)
 
 describe('cmdwin', function()
diff --git a/test/old/testdir/test_cmdline.vim b/test/old/testdir/test_cmdline.vim
index 6fa3ee5250..2f34ecb414 100644
--- a/test/old/testdir/test_cmdline.vim
+++ b/test/old/testdir/test_cmdline.vim
@@ -4036,6 +4036,27 @@ func Test_rulerformat_position()
   call StopVimInTerminal(buf)
 endfunc
 
+" Test for using "%!" in 'rulerformat' to use a function
+func Test_rulerformat_function()
+  CheckScreendump
+
+  let lines =<< trim END
+    func TestRulerFn()
+      return '10,20%=30%%'
+    endfunc
+  END
+  call writefile(lines, 'Xrulerformat_function', 'D')
+
+  let buf = RunVimInTerminal('-S Xrulerformat_function', #{rows: 2, cols: 40})
+  call term_sendkeys(buf, ":set ruler rulerformat=%!TestRulerFn()\<CR>")
+  call term_sendkeys(buf, ":redraw!\<CR>")
+  call term_wait(buf)
+  call VerifyScreenDump(buf, 'Test_rulerformat_function', {})
+
+  " clean up
+  call StopVimInTerminal(buf)
+endfunc
+
 func Test_getcompletion_usercmd()
   command! -nargs=* -complete=command TestCompletion echo <q-args>