1 files changed, 9 insertions, 1 deletions
diff --git a/test/functional/vimscript/timer_spec.lua b/test/functional/vimscript/timer_spec.lua
index e45b64422f..5463cfb234 100644
--- a/test/functional/vimscript/timer_spec.lua
+++ b/test/functional/vimscript/timer_spec.lua
@@ -96,7 +96,7 @@ describe('timers', function()
     nvim_async("command", "let g:val = 0 | let g:c = getchar()")
     retry(nil, nil, function()
       local val = eval("g:val")
-      ok(val >= 2, "expected >= 2, got: "..tostring(val))
+      ok(val >= 2, '>= 2', tostring(val))
       eq(0, eval("getchar(1)"))
     end)
     feed("c")
@@ -272,4 +272,12 @@ describe('timers', function()
     ]]
     eq("Vim(call):E48: Not allowed in sandbox", exc_exec("sandbox call timer_start(0, 'Scary')"))
   end)
+
+  it('can be triggered after an empty string <expr> mapping #17257', function()
+    local screen = Screen.new(40, 6)
+    screen:attach()
+    command([=[imap <expr> <F2> [timer_start(0, { _ -> execute("throw 'x'", "") }), ''][-1]]=])
+    feed('i<F2>')
+    screen:expect({any='E605: Exception not caught: x'})
+  end)
 end)