1 files changed, 24 insertions, 0 deletions
diff --git a/test/functional/plugin/msgpack_spec.lua b/test/functional/plugin/msgpack_spec.lua
index 18ff0f5156..9cbfacd936 100644
--- a/test/functional/plugin/msgpack_spec.lua
+++ b/test/functional/plugin/msgpack_spec.lua
@@ -697,3 +697,27 @@ describe('In autoload/msgpack.vim', function()
     end)
   end)
 end)
+
+describe('msgpackdump() function', function()
+  before_each(reset)
+
+  it('uses msgpack#string for dumping fref error messages for special map keys', function()
+    nvim_command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[{"_TYPE": v:msgpack_types.string, "_VAL": ["abc"]}, [function("tr")]]]}')
+    eq('Vim(call):E951: Error while dumping msgpackdump() argument, index 0, key ="abc" at index 0 from special map, index 0: attempt to dump function reference',
+       exc_exec('call msgpackdump([todump])'))
+  end)
+
+  it('falls back to using string() in case of error (fref)', function()
+    nvim_command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[[function("tr")], []]]}')
+    nvim_command('call add(todump._VAL[0][0], todump._VAL[0][0])')
+    eq('Vim(call):E951: Error while dumping msgpackdump() argument, index 0, key [function(\'tr\'), {E724@0}] at index 0 from special map, index 0: attempt to dump function reference',
+       exc_exec('call msgpackdump([todump])'))
+  end)
+
+  it('falls back to using string() in case of error (recurse)', function()
+    nvim_command('let todump = {"_TYPE": v:msgpack_types.map, "_VAL": [[[], []]]}')
+    nvim_command('call add(todump._VAL[0][0], todump._VAL[0][0])')
+    eq('Vim(call):E952: Unable to dump msgpackdump() argument, index 0: container references itself in key [{E724@0}] at index 0 from special map, index 0',
+       exc_exec('call msgpackdump([todump])'))
+  end)
+end)