chore: add GUT test framework

addons/gut/test/samples/two_pass_pending_fail.gd

@@ -0,0 +1,21 @@
+#A sample script for illustrating multiple scripts and what it looks like
+#when all tests pass.
+extends "res://addons/gut/test.gd"
+
+func test_pass_one():
+	assert_true(true, 'This is true')
+
+func test_pass_two():
+	assert_eq(1, 1, 'one is one in test two')
+
+func test_fail_one():
+	assert_true(false, 'false is not true')
+
+func test_fail_two():
+	assert_eq(3, 1, 'three is not one in test two')
+
+func test_pending_one():
+	pending('This one is pending')
+
+func test_pending_two():
+	pending('This is also pending')