Ledger: add a test method to show how to build a ZkAppCommand struct

CHANGELOG.md

@@ -36,6 +36,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#1493](https://github.com/o1-labs/mina-rust/pull/1493))
 - **Website**: add search bar with Algolia
   ([#1493](https://github.com/o1-labs/mina-rust/pull/1509))
+- **Ledger/ZkAppCommand**: show how to build a ZkAppCommand from scratch, with
+  dummy values ([#1514](https://github.com/o1-labs/mina-rust/pull/1514))
 
 ### Changed
 

ledger/src/scan_state/transaction_logic.rs

@@ -2319,7 +2319,7 @@ pub mod zkapp_command {
     /// <https://github.com/MinaProtocol/mina/blob/2ee6e004ba8c6a0541056076aab22ea162f7eb3a/src/lib/mina_base/account_update.ml#L758>
     #[derive(Debug, Clone, PartialEq)]
     pub struct Preconditions {
-        pub(crate) network: ZkAppPreconditions,
+        pub network: ZkAppPreconditions,
         pub account: AccountPreconditions,
         pub valid_while: Numeric<Slot>,
     }

ledger/tests/test_zkapp.rs

@@ -0,0 +1,122 @@
+// Run this test with:
+// cargo test --package mina-tree --test test_zkapp
+
+use ark_ff::Zero;
+use mina_curves::pasta::Fp;
+use mina_signer::Signature;
+use mina_tree::{
+    scan_state::{
+        currency::{Amount, Fee, Magnitude, Nonce, Sgn, Signed, Slot},
+        transaction_logic::{
+            zkapp_command::{
+                Account, AccountPreconditions, AccountUpdate, Actions, AuthorizationKind, Body,
+                CallForest, Control, Events, FeePayer, FeePayerBody, MayUseToken, Numeric,
+                Preconditions, Tree, Update, WithStackHash, ZkAppCommand, ZkAppPreconditions,
+            },
+            Memo,
+        },
+    },
+    MutableFp, TokenId,
+};
+
+#[test]
+fn test_zkapp_command_creation() {
+    // Create fee payer account
+    let fee_payer_pk = mina_signer::PubKey::from_address(
+        "B62qmnY6m4c6bdgSPnQGZriSaj9vuSjsfh6qkveGTsFX3yGA5ywRaja",
+    )
+    .unwrap()
+    .into_compressed();
+
+    // Create fee payer body
+    let fee_payer_body = FeePayerBody {
+        public_key: fee_payer_pk.clone(),
+        fee: Fee::from_u64(1000000),
+        valid_until: Some(Slot::from_u32(100000)),
+        nonce: Nonce::from_u32(0),
+    };
+
+    // Create fee payer with a dummy signature
+    let fee_payer = FeePayer {
+        body: fee_payer_body,
+        authorization: Signature::dummy(),
+    };
+
+    // Create an account update body
+    let account_update_pk = mina_signer::PubKey::from_address(
+        "B62qjVQLxt9nYMWGn45mkgwYfcz8e8jvjNCBo11VKJb7vxDNwv5QLPS",
+    )
+    .unwrap()
+    .into_compressed();
+
+    let account_update_body = Body {
+        public_key: account_update_pk.clone(),
+        token_id: TokenId::default(),
+        update: Update::noop(),
+        balance_change: Signed {
+            magnitude: Amount::zero(),
+            sgn: Sgn::Pos,
+        },
+        increment_nonce: false,
+        events: Events::empty(),
+        actions: Actions::empty(),
+        call_data: Fp::zero(),
+        preconditions: Preconditions {
+            network: ZkAppPreconditions::accept(),
+            account: AccountPreconditions(Account::accept()),
+            valid_while: Numeric::Ignore,
+        },
+        use_full_commitment: false,
+        implicit_account_creation_fee: false,
+        may_use_token: MayUseToken::No,
+        authorization_kind: AuthorizationKind::NoneGiven,
+    };
+
+    // Create account update
+    let account_update = AccountUpdate {
+        body: account_update_body,
+        authorization: Control::NoneGiven,
+    };
+
+    // Create a tree with the account update and empty calls
+    let tree = Tree {
+        account_update,
+        account_update_digest: MutableFp::new(Fp::zero()),
+        calls: CallForest::new(),
+    };
+
+    // Wrap tree in WithStackHash
+    let tree_with_hash = WithStackHash {
+        elt: tree,
+        stack_hash: MutableFp::new(Fp::zero()),
+    };
+
+    // Create call forest with the tree
+    let call_forest = CallForest(vec![tree_with_hash]);
+
+    // Ensure hashes are computed
+    call_forest.ensure_hashed();
+
+    // Create the zkApp command
+    let zkapp_command = ZkAppCommand {
+        fee_payer,
+        account_updates: call_forest,
+        memo: Memo::empty(),
+    };
+
+    // Verify basic properties
+    assert_eq!(zkapp_command.fee(), Fee::from_u64(1000000));
+    assert_eq!(zkapp_command.fee_payer().public_key, fee_payer_pk);
+    assert_eq!(zkapp_command.fee_token(), TokenId::default());
+
+    // Verify account updates - access the inner vector directly
+    assert_eq!(zkapp_command.account_updates.0.len(), 1);
+    assert_eq!(
+        zkapp_command.account_updates.0[0]
+            .elt
+            .account_update
+            .body
+            .public_key,
+        account_update_pk
+    );
+}