@Test public void testIdentity() throws Exception { Collection<Object> objects = new ArrayList<>(); objects.add("Hallo"); objects.add(55); objects.add(new ArithmeticException()); io.freefair.util.function.Function<Object, Object> identity = io.freefair.util.function.Functions.identity(); for (Object obj : objects) { assertSame(obj, identity.apply(obj)); } }