Add test for get_available_gas (#3751)

Closes #3499

commit-id:c7694535

---

**Stack**:
- #3756
- #3755
- #3752
- #3751 ⬅


⚠️ *Part of a stack created by [spr](https://github.com/ejoffe/spr). Do
not merge manually using the UI - doing so may have unexpected results.*

Author: ddoktorski

CHANGELOG.md

@@ -13,6 +13,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Minimal supported `Scarb` version is now `2.10.0` (updated from `2.9.1`)
 
+#### Fixed
+
+- [`core::testing::get_available_gas`](https://docs.starknet.io/build/corelib/core-testing-get_available_gas) now works correctly in snforge tests
+
 #### Removed
 
 - Possibility to use `#[available_gas]` with unnamed argument. Use named arguments instead, e.g. `#[available_gas(l2_gas: 5)]`.

crates/forge/tests/integration/get_available_gas.rs

@@ -0,0 +1,54 @@
+use forge_runner::forge_config::ForgeTrackedResource;
+use indoc::indoc;
+use std::path::Path;
+use test_utils::runner::{Contract, assert_passed};
+use test_utils::running_tests::run_test_case;
+use test_utils::test_case;
+
+#[test]
+fn test_get_available_gas() {
+    let test = test_case!(
+        indoc!(
+            r#"
+            use snforge_std::{declare, DeclareResultTrait, ContractClassTrait};
+
+            #[test]
+            fn check_available_gas() {
+                let contract = declare("HelloStarknet").unwrap().contract_class().clone();
+                let (contract_address, _) = contract.deploy(@ArrayTrait::new()).unwrap();
+
+                let gas_before = core::testing::get_available_gas();
+                core::gas::withdraw_gas().unwrap();
+
+                starknet::syscalls::call_contract_syscall(
+                    contract_address, selector!("increase_balance"), array![10].span(),
+                ).unwrap();
+
+                let gas_after = core::testing::get_available_gas();
+                core::gas::withdraw_gas().unwrap();
+
+                let gas_diff = gas_before - gas_after;
+
+                // call_contract syscall: 91_560 gas
+                // storage_write and storage_read syscalls: 10_000 gas each
+                let min_expected_gas = 91_560 + 10_000 * 2;
+
+                // Check that gas used is above the expected minimum
+                assert(gas_diff > min_expected_gas, 'Incorrect gas');
+
+                // Allow an arbitrary margin of 10_000 gas
+                assert(min_expected_gas + 10_000 > gas_diff, 'Incorrect gas');
+            }
+        "#
+        ),
+        Contract::from_code_path(
+            "HelloStarknet".to_string(),
+            Path::new("tests/data/contracts/hello_starknet.cairo"),
+        )
+        .unwrap()
+    );
+
+    let result = run_test_case(&test, ForgeTrackedResource::SierraGas);
+
+    assert_passed(&result);
+}

crates/forge/tests/integration/mod.rs

@@ -16,6 +16,7 @@ mod env;
 mod fuzzing;
 mod gas;
 mod generate_random_felt;
+mod get_available_gas;
 mod get_class_hash;
 mod interact_with_state;
 mod l1_handler_executor;