* hashCode, and compareTo in counter.
   */
  static List<CountsHashCodeAndEquals> createAdversarialInput(int power, CallsCounter counter) {
    String str1 = "Aa";
    String str2 = "BB";
    assertEquals(str1.hashCode(), str2.hashCode());
    List<String> haveSameHashes2 = Arrays.asList(str1, str2);
    List<CountsHashCodeAndEquals> result =
        Lists.newArrayList(