chore: add GUT test framework

addons/gut/test/integration/test_sample_all_passed_integration.gd

@@ -0,0 +1,12 @@
+#A sample script for illustrating multiple scripts and what it looks like
+#when all tests pass.
+extends "res://addons/gut/test.gd"
+
+func test_works():
+	assert_true(true, 'This is true')
+
+func test_two():
+	assert_eq("two", "two", "This is also true")
+
+func test_3():
+	assert_ne("one", "two", "This is yet again true")