@Test
public void invokeListOfStrings() {

    FunctionTestUtil.assertResult(maxFunction.invoke(Collections.singletonList("a")), "a");
    FunctionTestUtil.assertResult(maxFunction.invoke(Arrays.asList("a", "b", "c")), "c");
    FunctionTestUtil.assertResult(maxFunction.invoke(Arrays.asList("a", "c", "b")), "c");
    FunctionTestUtil.assertResult(maxFunction.invoke(Arrays.asList("c", "a", "b")), "c");
}