BTreeSet::new(),
      recipient(),
      [change(0), change(1)],
      FeeRate::try_from(1.0).unwrap(),
      Target::Postage,
    )
    .select_outgoing()
    .unwrap()
    .strip_value()
    .build()
    .unwrap();
  }

  #[test]
  #[should_panic(expected = "invariant: recipient address appears exactly once in outputs")]
  fn invariant_recipient_appears_exactly_once() {
    let mut amounts = BTreeMap::new();
    amounts.insert(outpoint(1), Amount::from_sat(5_000));
    amounts.insert(outpoint(2), Amount::from_sat(5_000));
    amounts.insert(outpoint(3), Amount::from_sat(2_000));

    TransactionBuilder {
      amounts,
      fee_rate: FeeRate::try_from(1.0).unwrap(),
      utxos: BTreeSet::new(),
      locked_utxos: BTreeSet::new(),
      outgoing: satpoint(1, 0),
      inscriptions: BTreeMap::new(),
      recipient: recipient(),
      unused_change_addresses: vec![change(0), change(1)],
      change_addresses: vec![change(0), change(1)].into_iter().collect(),
      inputs: vec![outpoint(1), outpoint(2), outpoint(3)],