@Test
public void invokeListOfStrings() {

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