chore: add GUT test framework

addons/gut/scratch/demo_reload_error.gd

@@ -0,0 +1,21 @@
+# Demo for https://github.com/godotengine/godot/issues/65263
+extends SceneTree
+
+func _init():
+	var script_source = '' + \
+	"func hello_world():\n" + \
+	"\tprint('--- hello world ---')"
+
+	print(script_source)
+
+	var DynScript = GDScript.new()
+	DynScript.source_code = script_source
+	DynScript.resource_path = 'workaround for godot issue #65263'
+	print('pre-reload')
+	DynScript.reload()
+	print('post-reload')
+
+	var inst = DynScript.new()
+	inst.hello_world()
+
+	quit()