fn invariant_all_output_are_recognized() {
    let utxos = vec![(outpoint(1), Amount::from_sat(10_000))];

    let mut builder = TransactionBuilder::new(
      satpoint(1, 3_333),
      BTreeMap::new(),
      utxos.into_iter().collect(),
      BTreeSet::new(),
      recipient(),
      [change(0), change(1)],
      FeeRate::try_from(1.0).unwrap(),
      Target::Postage,
    )
    .select_outgoing()
    .unwrap()
    .align_outgoing()
    .add_value()
    .unwrap()
    .strip_value()
    .deduct_fee();

    builder.change_addresses = BTreeSet::new();

    builder.build().unwrap();
  }

  #[test]
  #[should_panic(expected = "invariant: all outputs are above dust limit")]
  fn invariant_all_output_are_above_dust_limit() {
    let utxos = vec![(outpoint(1), Amount::from_sat(10_000))];

    TransactionBuilder::new(
      satpoint(1, 1),
      BTreeMap::new(),
      utxos.into_iter().collect(),
      BTreeSet::new(),
      recipient(),
      [change(0), change(1)],
      FeeRate::try_from(1.0).unwrap(),
      Target::Postage,