chore: add GUT test framework

addons/gut/test/unit/test_command_line_auto_load.gd

@@ -0,0 +1,10 @@
+# ------------------------------------------------------------------------------
+# A sample script for illustrating multiple scripts and what it looks like
+# when all tests pass.
+# ------------------------------------------------------------------------------
+extends "res://addons/gut/test.gd"
+
+func test_auto_load_works():
+	var g = get_node("/root/global")
+	g.print_loaded()
+	pass_test("should get here")