blockifier_test_utils: add create_multicall_calldata helper (#14108)

Serializes a sequence of calls as `Array<Call>` for use as Cairo 1 account
multicall calldata. Matches `starknet_rust::accounts::ExecutionEncoding::New`.
Replaces ad-hoc serialization in `prove_and_verify_multicall_tx` and the
private `single_multicall_data` helper in `cende_blob_regression_test`.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: AvivYossef-starkware

crates/blockifier_test_utils/src/calldata.rs

@@ -37,6 +37,19 @@ pub fn create_calldata(
     )
 }
 
+/// Serializes calls as the canonical Cairo 1 `Array<Call>` payload:
+/// `[num_calls, (to, selector, calldata_len, *calldata)*]`.
+pub fn create_multicall_calldata(calls: &[(ContractAddress, &str, &[Felt])]) -> Vec<Felt> {
+    let mut buf = vec![felt!(u64_from_usize(calls.len()))];
+    for (to, entry_point_name, args) in calls {
+        buf.push(*to.0.key());
+        buf.push(selector_from_name(entry_point_name).0);
+        buf.push(felt!(u64_from_usize(args.len())));
+        buf.extend_from_slice(args);
+    }
+    buf
+}
+
 /// Calldata for a trivial entry point in the [`crate::contracts::FeatureContract`] TestContract.
 /// The calldata is formatted for using the featured contracts AccountWithLongValidate or
 /// AccountWithoutValidations as account contract.

crates/central_systest_blobs/src/cende_blob_regression_test.rs

@@ -35,7 +35,7 @@ use blockifier::transaction::account_transaction::AccountTransaction as Blockifi
 use blockifier::transaction::transaction_execution::Transaction as BlockifierTx;
 use blockifier::transaction::transactions::ExecutableTransaction;
 use blockifier_test_utils::cairo_versions::{CairoVersion, RunnableCairo1};
-use blockifier_test_utils::calldata::create_calldata;
+use blockifier_test_utils::calldata::create_multicall_calldata;
 use blockifier_test_utils::contracts::FeatureContract;
 use expect_test::{expect, expect_file, Expect};
 use google_cloud_storage::client::{Client, ClientConfig};
@@ -447,15 +447,6 @@ impl BlobFactory {
         TransactionSignature(Arc::new(vec![sig.r, sig.s]))
     }
 
-    fn single_multicall_data(
-        address: ContractAddress,
-        function_name: &str,
-        calldata: &[Felt],
-    ) -> Calldata {
-        let single_calldata = create_calldata(address, function_name, calldata);
-        Calldata(Arc::new([vec![Felt::ONE], single_calldata.0.as_slice().to_vec()].concat()))
-    }
-
     /// If the sender address is None, create a bootstrap declare tx.
     /// Otherwise, create a regular declare tx (with fees).
     fn make_declare_tx(&mut self, contract: FeatureContract, sender: Option<ContractAddress>) {
@@ -603,7 +594,8 @@ impl BlobFactory {
         } else {
             AllResourceBounds::new_unlimited_gas_no_fee_enforcement()
         };
-        let calldata = Self::single_multicall_data(address, function_name, calldata);
+        let calldata =
+            Calldata(create_multicall_calldata(&[(address, function_name, calldata)]).into());
         let rpc_tx_unsigned = InternalRpcInvokeTransactionV3 {
             sender_address: *OPERATOR_ADDRESS,
             calldata,

crates/starknet_os_flow_tests/src/virtual_os_test.rs

@@ -5,7 +5,7 @@ use blockifier::test_utils::dict_state_reader::DictStateReader;
 use blockifier::test_utils::get_valid_virtual_os_program_hash;
 use blockifier::transaction::test_utils::ExpectedExecutionInfo;
 use blockifier_test_utils::cairo_versions::{CairoVersion, RunnableCairo1};
-use blockifier_test_utils::calldata::create_calldata;
+use blockifier_test_utils::calldata::{create_calldata, create_multicall_calldata};
 use blockifier_test_utils::contracts::FeatureContract;
 use rstest::rstest;
 use starknet_api::abi::abi_utils::selector_from_name;
@@ -285,21 +285,13 @@ async fn prove_and_verify_multicall_tx() {
         TestBuilder::create_standard_virtual([(test_contract, calldata![Felt::ONE, Felt::TWO])])
             .await;
 
-    // Appends a single `Call` entry to `multi_call_args` as
-    // `[to, selector, calldata_len, *calldata]` and bumps the leading `num_calls`
-    // counter. All inner calls in this test target the same test contract.
-    let mut multi_call_args: Vec<Felt> = vec![Felt::ZERO];
-    let mut serialize_call = |func_name: &str, args: &[Felt]| {
-        multi_call_args[0] += Felt::ONE;
-        multi_call_args.push(*contract_address.0.key());
-        multi_call_args.push(selector_from_name(func_name).0);
-        multi_call_args.push(Felt::from(args.len()));
-        multi_call_args.extend_from_slice(args);
-    };
-
     // TODO(Yoni): add more inner calls (e.g. sha256, secp256k1, send_message_to_l1).
-    serialize_call("test_keccak", &[]);
-    serialize_call("test_ec_op", &[]);
+    // TODO(Yoni): restore the keccak inner call once the keccak syscall is allowed in
+    // virtual OS mode (added in a follow-up PR stacked on top of this one).
+    let multi_call_args = create_multicall_calldata(&[
+        // (contract_address, "test_keccak", &[]),
+        (contract_address, "test_ec_op", &[]),
+    ]);
 
     // The dummy account's `__execute__(contract_address, selector, calldata)` forwards
     // to its own `multi_call` entry point.