### Question:
StringUtils { public static Optional<Tuple<String, String>> splitIntoTwo(String mappingString) { if (mappingString == null || !mappingString.contains("->")) return Optional.empty(); String[] params = mappingString.split("->"); if (params.length != 2) { return Optional.empty(); } return Optional.of(new Tuple<>(notEmptytrimmed(params[0]), notEmptytrimmed(params[1]))); }  static String arrayFormat(String format, Object[] items); static Optional<String> cdr(String name, String... sep); static String car(String name, String... sep); static String lastOf(String qualifiedName, String... sep); static String untill(String qualifiedName, String... sep); static String dotToUpperCamelCase(String input); static String dotToDash(String input); static String camelCaseToDash(String input); static boolean isPackageFriendly(String moduleName); static String withoutTypeArgs(String javaTypeString); static String notEmptytrimmed(String param); static Optional<Tuple<String, String>> splitIntoTwo(String mappingString); static int countMatches(String theString, String... sep);  }### Answer:
@Test void test_splitInTwo() { assertEquals(Optional.empty(),StringUtils.splitIntoTwo(null)); assertEquals(Optional.empty(),StringUtils.splitIntoTwo("")); assertEquals(Optional.empty(),StringUtils.splitIntoTwo("->->")); assertEquals(Optional.of(new Tuple<>("a", "b")),StringUtils.splitIntoTwo("a->b")); }