From e2e2438e96de3ec916df1bfd21fdb8068ec40bea Mon Sep 17 00:00:00 2001
From: Yonatan-Starkware <yonatan.k@starkware.co>
Date: Wed, 20 Aug 2025 16:39:51 +0300
Subject: [PATCH] starknet_os: validate_builtins function

---
 crates/starknet_os/src/runner.rs           | 4 +++-
 crates/starknet_os/src/test_utils/utils.rs | 8 ++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/crates/starknet_os/src/runner.rs b/crates/starknet_os/src/runner.rs
index cafa8052459..8d171a4932b 100644
--- a/crates/starknet_os/src/runner.rs
+++ b/crates/starknet_os/src/runner.rs
@@ -208,7 +208,7 @@ pub fn run_os_for_testing<S: StateReader>(
     }: OsHints,
     state_readers: Vec<S>,
 ) -> Result<(StarknetOsRunnerOutput, Vec<OsTransactionTrace>), StarknetOsError> {
-    let (runner_output, snos_hint_processor) = create_hint_processor_and_run_os(
+    let (mut runner_output, snos_hint_processor) = create_hint_processor_and_run_os(
         layout,
         os_hints_config,
         &os_block_inputs,
@@ -220,6 +220,8 @@ pub fn run_os_for_testing<S: StateReader>(
         public_key_y,
     )?;
 
+    crate::test_utils::utils::validate_builtins(&mut runner_output.cairo_runner);
+
     let txs_trace: Vec<OsTransactionTrace> =
         snos_hint_processor.get_current_execution_helper().unwrap().os_logger.get_txs().clone();
 
diff --git a/crates/starknet_os/src/test_utils/utils.rs b/crates/starknet_os/src/test_utils/utils.rs
index bf35c6bd11c..54351fb30c7 100644
--- a/crates/starknet_os/src/test_utils/utils.rs
+++ b/crates/starknet_os/src/test_utils/utils.rs
@@ -5,6 +5,7 @@ use std::sync::LazyLock;
 use cairo_vm::hint_processor::builtin_hint_processor::dict_hint_utils::DICT_ACCESS_SIZE;
 use cairo_vm::types::layout_name::LayoutName;
 use cairo_vm::types::relocatable::{MaybeRelocatable, Relocatable};
+use cairo_vm::vm::runners::cairo_runner::CairoRunner;
 use cairo_vm::vm::vm_core::VirtualMachine;
 use ethnum::U256;
 use num_bigint::{BigInt, Sign};
@@ -157,3 +158,10 @@ pub(crate) fn get_entrypoint_runner_config() -> EntryPointRunnerConfig {
         ..Default::default()
     }
 }
+
+pub(crate) fn validate_builtins(runner: &mut CairoRunner) {
+    let builtins_start = runner.get_builtins_final_stack(runner.vm.get_ap()).unwrap();
+    let n_builtins = runner.get_program().builtins_len();
+    let builtins_end = runner.vm.get_ap();
+    assert_eq!((builtins_start + n_builtins).unwrap(), builtins_end);
+}