public void testCartesianProduct_binary1x2() {
    assertThat(cartesianProduct(list(1), list(2, 3)))
        .containsExactly(list(1, 2), list(1, 3))
        .inOrder();
  }

  public void testCartesianProduct_binary2x2() {
    assertThat(cartesianProduct(list(1, 2), list(3, 4)))
        .containsExactly(list(1, 3), list(1, 4), list(2, 3), list(2, 4))
        .inOrder();
  }

  public void testCartesianProduct_2x2x2() {