#unittest {
	name: "upper() and lower methods for string";
	error: NONE;
	result: true;
};

func main () {
	var s = "Hello World"
	var u = s.upper() == "HELLO WORLD"
	var l = s.lower() == "hello world"

	// calling the method returns the change, but should not physically change the
	// base string
	s.upper()
	var unchanged_u = s == "Hello World"

	s.lower()
	var unchanged_l = s == "Hello World"

	return u and l and unchanged_u and unchanged_l
}