svoid test_reversedSubstring() {
  assertEqualsVerbose(reversedSubstring("abcd", 2, 4), "dc");
  assertEqualsVerbose(reversedSubstring("abcd", 2, 5), "dc");
  assertEqualsVerbose(reversedSubstring("abc", -3, 2), "ba");
  assertEqualsVerbose(reversedSubstring("abc", 2, 1), "");
}