TOOLS: add a stupid test program for Lua async commands

TOOLS/lua/command-test.lua

@@ -0,0 +1,53 @@
+-- Test script for some command API details.
+
+local utils = require("mp.utils")
+
+function join(sep, arr, count)
+    local r = ""
+    if count == nil then
+        count = #arr
+    end
+    for i = 1, count do
+        if i > 1 then
+            r = r .. sep
+        end
+        r = r .. utils.to_string(arr[i])
+    end
+    return r
+end
+
+mp.observe_property("vo-configured", "bool", function(_, v)
+    if v ~= true then
+        return
+    end
+
+    print("async expand-text")
+    mp.command_native_async({"expand-text", "hello ${path}!"},
+        function(res, val, err)
+            print("done async expand-text: " .. join(" ", {res, val, err}))
+        end)
+
+    -- make screenshot writing very slow
+    mp.set_property("screenshot-format", "png")
+    mp.set_property("screenshot-png-compression", "9")
+
+    timer = mp.add_periodic_timer(0.1, function() print("I'm alive") end)
+    timer:resume()
+
+    print("Slow screenshot command...")
+    res, err = mp.command_native({"screenshot"})
+    print("done, res: " .. utils.to_string(res))
+
+    print("Slow screenshot async command...")
+    res, err = mp.command_native_async({"screenshot"}, function(res)
+        print("done (async), res: " .. utils.to_string(res))
+        timer:kill()
+    end)
+    print("done (sending), res: " .. utils.to_string(res))
+
+    print("Broken screenshot async command...")
+    mp.command_native_async({"screenshot-to-file", "/nonexistent/bogus.png"},
+        function(res, val, err)
+            print("done err scr.: " .. join(" ", {res, val, err}))
+        end)
+end)