zcash_client_backend: Make `data_api` traits delegatable via `ambassador` for testing.

Cargo.lock

@@ -67,6 +67,18 @@ version = "0.2.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5c6cb57a04249c6480766f7f7cef5467412af1490f8d1e243141daddada3264f"
 
+[[package]]
+name = "ambassador"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6b27ba24e4d8a188489d5a03c7fabc167a60809a383cdb4d15feb37479cd2a48"
+dependencies = [
+ "itertools 0.10.5",
+ "proc-macro2",
+ "quote",
+ "syn 1.0.109",
+]
+
 [[package]]
 name = "amplify"
 version = "4.6.0"
@@ -5817,6 +5829,7 @@ dependencies = [
 name = "zcash_client_backend"
 version = "0.13.0"
 dependencies = [
+ "ambassador",
  "arti-client",
  "assert_matches",
  "async-trait",
@@ -5879,6 +5892,7 @@ dependencies = [
 name = "zcash_client_sqlite"
 version = "0.11.2"
 dependencies = [
+ "ambassador",
  "assert_matches",
  "bip32",
  "bls12_381",

Cargo.toml

@@ -133,6 +133,7 @@ lazy_static = "1"
 static_assertions = "1"
 
 # Tests and benchmarks
+ambassador = "0.4"
 assert_matches = "1.5"
 criterion = "0.5"
 proptest = "1"

zcash_client_backend/Cargo.toml

@@ -91,6 +91,7 @@ shardtree.workspace = true
 # - Test dependencies
 proptest = { workspace = true, optional = true }
 jubjub = { workspace = true, optional = true }
+ambassador = { workspace = true, optional = true }
 
 # - ZIP 321
 nom = "7"
@@ -195,6 +196,7 @@ tor = [
 
 ## Exposes APIs that are useful for testing, such as `proptest` strategies.
 test-dependencies = [
+    "dep:ambassador",
     "dep:proptest",
     "dep:jubjub",
     "orchard?/test-dependencies",

zcash_client_backend/src/data_api.rs

@@ -103,7 +103,7 @@ use {
 };
 
 #[cfg(any(test, feature = "test-dependencies"))]
-use zcash_primitives::consensus::NetworkUpgrade;
+use {ambassador::delegatable_trait, zcash_primitives::consensus::NetworkUpgrade};
 
 pub mod chain;
 pub mod error;
@@ -662,12 +662,22 @@ impl<NoteRef> SpendableNotes<NoteRef> {
         self.sapling.as_ref()
     }
 
+    /// Consumes this value and returns the Sapling notes contained within it.
+    pub fn take_sapling(self) -> Vec<ReceivedNote<NoteRef, sapling::Note>> {
+        self.sapling
+    }
+
     /// Returns the set of spendable Orchard notes.
     #[cfg(feature = "orchard")]
     pub fn orchard(&self) -> &[ReceivedNote<NoteRef, orchard::note::Note>] {
         self.orchard.as_ref()
     }
 
+    /// Consumes this value and returns the Orchard notes contained within it.
+    pub fn take_orchard(self) -> Vec<ReceivedNote<NoteRef, orchard::note::Note>> {
+        self.orchard
+    }
+
     /// Computes the total value of Sapling notes.
     pub fn sapling_value(&self) -> Result<NonNegativeAmount, BalanceError> {
         self.sapling
@@ -721,6 +731,7 @@ impl<NoteRef> SpendableNotes<NoteRef> {
 
 /// A trait representing the capability to query a data store for unspent transaction outputs
 /// belonging to a wallet.
+#[cfg_attr(feature = "test-dependencies", delegatable_trait)]
 pub trait InputSource {
     /// The type of errors produced by a wallet backend.
     type Error: Debug;
@@ -798,6 +809,7 @@ pub trait InputSource {
 /// This trait defines the read-only portion of the storage interface atop which
 /// higher-level wallet operations are implemented. It serves to allow wallet functions to
 /// be abstracted away from any particular data storage substrate.
+#[cfg_attr(feature = "test-dependencies", delegatable_trait)]
 pub trait WalletRead {
     /// The type of errors that may be generated when querying a wallet data store.
     type Error: Debug;
@@ -1773,6 +1785,7 @@ impl AccountBirthday {
 /// [zcash/librustzcash#1284]: https://github.com/zcash/librustzcash/issues/1284
 /// [BIP 39]: https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki
 /// [`bip0039`]: https://crates.io/crates/bip0039
+#[cfg_attr(feature = "test-dependencies", delegatable_trait)]
 pub trait WalletWrite: WalletRead {
     /// The type of identifiers used to look up transparent UTXOs.
     type UtxoRef;
@@ -1974,9 +1987,7 @@ pub trait WalletWrite: WalletRead {
 }
 
 /// This trait describes a capability for manipulating wallet note commitment trees.
-///
-/// At present, this only serves the Sapling protocol, but it will be modified to
-/// also provide operations related to Orchard note commitment trees in the future.
+#[cfg_attr(feature = "test-dependencies", delegatable_trait)]
 pub trait WalletCommitmentTrees {
     type Error: Debug;