fix(f_wait): flush UI before blocking (#25962)

1 files changed, 48 insertions, 11 deletions

diff --git a/test/functional/ui/messages_spec.lua b/test/functional/ui/messages_spec.lua
index a5b2474bc5..215e763fd1 100644
--- a/test/functional/ui/messages_spec.lua
+++ b/test/functional/ui/messages_spec.lua
@@ -1312,17 +1312,54 @@ vimComment     xxx match /\s"[^\-:.%#=*].*$/ms=s+1,lc=1  excludenl contains=@vim
     ]])
   end)
 
-  it('echo messages are shown correctly when getchar() immediately follows', function()
-    feed([[:echo 'foo' | echo 'bar' | call getchar()<CR>]])
-    screen:expect([[
-                                                                  |
-      {1:~                                                           }|
-      {1:~                                                           }|
-      {1:~                                                           }|
-      {3:                                                            }|
-      foo                                                         |
-      bar^                                                         |
-    ]])
+  describe('echo messages are shown when immediately followed by', function()
+    --- @param to_block  string           command to cause a blocking wait
+    --- @param to_unblock  number|string  number: timeout for blocking screen
+    ---                                   string: keys to stop the blocking wait
+    local function test_flush_before_block(to_block, to_unblock)
+      local timeout = type(to_unblock) == 'number' and to_unblock or nil
+      exec(([[
+        func PrintAndWait()
+          echon "aaa\nbbb"
+          %s
+          echon "\nccc"
+        endfunc
+      ]]):format(to_block))
+      feed(':call PrintAndWait()<CR>')
+      screen:expect{grid=[[
+                                                                    |
+        {1:~                                                           }|
+        {1:~                                                           }|
+        {1:~                                                           }|
+        {3:                                                            }|
+        aaa                                                         |
+        bbb^                                                         |
+      ]], timeout=timeout}
+      if type(to_unblock) == 'string' then
+        feed(to_unblock)
+      end
+      screen:expect{grid=[[
+                                                                    |
+        {1:~                                                           }|
+        {3:                                                            }|
+        aaa                                                         |
+        bbb                                                         |
+        ccc                                                         |
+        {4:Press ENTER or type command to continue}^                     |
+      ]]}
+    end
+
+    it('getchar()', function()
+      test_flush_before_block([[call getchar()]], 'k')
+    end)
+
+    it('wait()', function()
+      test_flush_before_block([[call wait(300, '0')]], 100)
+    end)
+
+    it('lua vim.wait()', function()
+      test_flush_before_block([[lua vim.wait(300, function() end)]], 100)
+    end)
   end)
 
   it('consecutive calls to win_move_statusline() work after multiline message #21014',function()