assertThat(actual.lastIndexOf(list(1))).isEqualTo(-1);
    assertThat(actual.lastIndexOf(list(1, 1, 1))).isEqualTo(-1);
  }

  public void testCartesianProduct_unrelatedTypes() {
    List<Integer> x = list(1, 2);
    List<String> y = list("3", "4");

    List<Object> exp1 = list((Object) 1, "3");
    List<Object> exp2 = list((Object) 1, "4");

    new EqualsTester()
        .addEqualityGroup(cartesian, equivalent)
        .addEqualityGroup(different1)
        .addEqualityGroup(different2)
        .testEquals();
  }

  public void testCartesianProduct_unrelatedTypes() {
    Set<Integer> x = set(1, 2);
    Set<String> y = set("3", "4");

    List<Object> exp1 = list((Object) 1, "3");
    List<Object> exp2 = list((Object) 1, "4");