chore: add GUT test framework

addons/gut/test/unit/verify_signal_watches_are_cleared.gd

@@ -0,0 +1,23 @@
+# ------------------------------------------------------------------------------
+#
+# This test script is run manually by test_gut.gd to verify that watched
+# signals are cleared between tests.
+#
+# ------------------------------------------------------------------------------
+extends "res://addons/gut/test.gd"
+
+class SignalObject:
+	func _init():
+		add_user_signal('the_signal')
+
+var the_signal_object = SignalObject.new()
+
+func test_watch_and_emit_a_signal():
+	watch_signals(the_signal_object)
+	the_signal_object.emit_signal('the_signal')
+	assert_signal_emitted(the_signal_object, 'the_signal')
+
+func test_make_sure_not_watching_anymore():
+	# this should fail because the object should not be watched anymore,
+	# it is verified in the test that runs this script
+	assert_signal_emitted(the_signal_object, 'the_signal')