Merge #418: feat(wallet): add LoadParams::two_path_descriptor method

c4dbe42 feat(wallet): add `LoadParams::two_path_descriptor` method (Yuki Kishimoto)

Pull request description:

  ### Description

  Added `LoadParams::two_path_descriptor` to validate that both the external and internal wallet descriptors match an expected two-path descriptor during load.

  ### Changelog notice

  - Add `LoadParams::two_path_descriptor` method

  ### Checklists

  #### All Submissions:

  * [X] I've signed all my commits
  * [X] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
  * [X] I ran `just p` before pushing

  #### New Features:

  * [X] I've added tests for the new feature
  * [X] I've added docs for the new feature

ACKs for top commit:
  ValuedMammal:
    ACK c4dbe42
  Dmenec:
    ACK c4dbe42

Tree-SHA512: 7afe2cf7b6752fa7e52f5f47b5066e8ea5af894dbcb1df9c0cdfecf7eaffa43158b2cd5fc225d7892ec01933ea88e0dadd8700de92688911809727ad5283bb6f

Author: ValuedMammal

src/test_utils.rs

@@ -147,6 +147,11 @@ pub fn get_test_wpkh_and_change_desc() -> (&'static str, &'static str) {
     "wpkh(tprv8ZgxMBicQKsPdy6LMhUtFHAgpocR8GC6QmwMSFpZs7h6Eziw3SpThFfczTDh5rW2krkqffa11UpX3XkeTTB2FvzZKWXqPY54Y6Rq4AQ5R8L/84'/1'/0'/1/*)")
 }
 
+/// `wpkh` two-path descriptor
+pub fn get_test_two_path_wpkh() -> &'static str {
+    "wpkh(tpubDDks68wKK1xKaVVVbNmXUAx68K1K817M6KwjvjEyCrjdU7xMvjKnfYAtZjfZcrfPfGFzqmibuVqMzKJGbBnK7mo7WSJri8Y9QgM7aNQ3fCp/<0;1>/*)"
+}
+
 /// `wsh` descriptor with policy `and(pk(A),older(6))`
 pub fn get_test_single_sig_csv() -> &'static str {
     "wsh(and_v(v:pk(cVpPVruEDdmutPzisEsYvtST1usBR3ntr8pXSyt6D2YYqXRyPcFW),older(6)))"

src/wallet/params.rs

@@ -270,6 +270,28 @@ impl LoadParams {
         self
     }
 
+    /// Checks that the provided two-path descriptor matches exactly what is loaded for both the
+    /// external and internal keychains.
+    ///
+    /// # Note
+    ///
+    /// You must also specify [`extract_keys`](Self::extract_keys) if you wish to add a signer
+    /// for an expected descriptor containing secrets.
+    pub fn two_path_descriptor<D>(mut self, expected_descriptor: D) -> Self
+    where
+        D: IntoWalletDescriptor + Send + Clone + 'static,
+    {
+        let external: DescriptorToExtract =
+            make_two_path_descriptor_to_extract(expected_descriptor.clone(), 0);
+        let internal: DescriptorToExtract =
+            make_two_path_descriptor_to_extract(expected_descriptor, 1);
+
+        self.check_descriptor = Some(Some(external));
+        self.check_change_descriptor = Some(Some(internal));
+
+        self
+    }
+
     /// Checks that the given network matches the one loaded from persistence.
     pub fn check_network(mut self, network: Network) -> Self {
         self.check_network = Some(network);

tests/persisted_wallet.rs

@@ -427,6 +427,31 @@ fn single_descriptor_wallet_persist_and_recover() {
     );
 }
 
+#[test]
+fn two_path_descriptor_wallet_persist_and_recover() {
+    use bdk_chain::rusqlite;
+
+    let temp_dir = tempfile::tempdir().unwrap();
+    let db_path = temp_dir.path().join("wallet.db");
+    let mut db = rusqlite::Connection::open(db_path).unwrap();
+
+    let two_path_descriptor = get_test_two_path_wpkh();
+    let mut wallet = Wallet::create_from_two_path_descriptor(two_path_descriptor)
+        .network(Network::Testnet4)
+        .create_wallet(&mut db)
+        .unwrap();
+    let _ = wallet.reveal_addresses_to(KeychainKind::External, 2);
+    assert!(wallet.persist(&mut db).unwrap());
+
+    let loaded = Wallet::load()
+        .two_path_descriptor(two_path_descriptor)
+        .check_network(Network::Testnet4)
+        .load_wallet(&mut db)
+        .unwrap()
+        .expect("wallet must exist");
+    assert_eq!(loaded.derivation_index(KeychainKind::External), Some(2));
+}
+
 #[test]
 fn wallet_changeset_is_persisted() {
     persist_wallet_changeset("store.db", |path| {