chore: add GUT test framework

addons/gut/test/unit/test_nothing.gd

@@ -0,0 +1,43 @@
+extends GutTest
+# ------------------------------------------------------------------------------
+# This test script is used for spot checking orphans created by GUT.  If you
+# run GUT with just this script, and you get engine warnings about orphans or
+# resources still in use, then GUT has a problem.
+# ------------------------------------------------------------------------------
+func test_true():
+	assert_true(true)
+
+func test_false():
+	assert_false(false)
+
+func test_eq_n():
+	assert_eq(1, 1)
+
+func test_eq_s():
+	assert_eq('a', 'a')
+
+func test_with_double_of_script():
+	var d = double(load('res://test/resources/doubler_test_objects/double_me.gd')).new()
+	assert_not_null(d)
+
+func test_with_double_of_scene():
+	var d = double(load('res://test/resources/doubler_test_objects/double_me_scene.tscn')).instantiate()
+	assert_not_null(d)
+
+func test_with_script_partial_double_of_script():
+	var d = partial_double(load('res://test/resources/doubler_test_objects/double_me.gd')).new()
+	assert_not_null(d)
+
+func test_with_partial_double_of_scene():
+	var d = partial_double(load('res://test/resources/doubler_test_objects/double_me_scene.tscn')).instantiate()
+	assert_not_null(d)
+
+func test_with_spy_on_double_of_script():
+	var d = double(load('res://test/resources/doubler_test_objects/double_me.gd')).new()
+	d.get_value()
+	assert_called(d, 'get_value')
+
+func test_with_spy_on_partial_double_of_scene():
+	var d = partial_double(load('res://test/resources/doubler_test_objects/double_me_scene.tscn')).instantiate()
+	d.return_hello()
+	assert_called(d, 'return_hello')