chore: add GUT test framework

addons/gut/test/resources/stub_test_objects/to_stub.gd

@@ -0,0 +1,40 @@
+# ------------------------------------------------------------------------------
+# this class is used by test_stubber and represents a doubled object.
+# This top section must be kept in line with script_template.txt
+# ------------------------------------------------------------------------------
+var __gutdbl_values = {
+	thepath = 'res://test/resources/stub_test_objects/to_stub.gd',
+	subpath = '',
+	stubber = -1,
+	spy = -1,
+	gut = -1,
+	singleton_name = '',
+	singleton = -1,
+	is_partial = false,
+}
+var __gutdbl = load('res://addons/gut/double_tools.gd').new(self)
+
+# Here so other things can check for a method to know if this is a double.
+func __gutdbl_check_method__():
+	pass
+
+
+# Cleanup called by GUT after tests have finished.  Important for RefCounted
+# objects.  Nodes are freed, and won't have this method called on them.
+func __gutdbl_done():
+	__gutdbl = null
+	__gutdbl_values.clear()
+
+# ------------------------------------------------------------------------------
+# These are some methods and vars to be used in tests.
+# ------------------------------------------------------------------------------
+var value = 4
+func get_value():
+	return value
+
+func set_value(val):
+	value = val
+
+
+func default_value_method(p1='a'):
+	pass