chore: add GUT test framework

addons/gut/test/resources/wait_awhile.gd

@@ -0,0 +1,13 @@
+extends GutTest
+# ------------------------------------------------------------------------------
+# This is used to give you some time to do stuff before a test script is run.
+# This is intended to be used with -gtest option from the command line (hence
+# this file does not have the test_ prefix and it is in the resources dir).
+# ------------------------------------------------------------------------------
+var seconds_to_wait = 10
+
+func test_this_waits_for_a_bit():
+	for i in range(seconds_to_wait):
+		gut.p(seconds_to_wait - i)
+		await wait_seconds(1)
+	pass_test("This passes because it just waits")