added a test for storage of a zero

contracts/issues/Ndev3234.sol

@@ -0,0 +1,24 @@
+pragma solidity 0.8.12;
+
+contract saveZeros {
+
+    bytes32[64] public b;  // prefills the contract storage
+    bytes32 public number;
+    mapping(uint256 => uint256) public intMapping;
+
+    function saveZeroToVar() public returns (bytes32) {  // should not create a new account
+        number = bytes32(0);
+        return number;
+    }
+
+    function saveZeroToMapping() public {  // should not create a new account
+        intMapping[0] = 0;
+    }
+
+    function saveZeroToMappingCycle() public {  // should not create a new account
+        for (uint i = 0; i < 10; i++) {
+            intMapping[i] = 0;
+        }
+    }
+
+}

integration/tests/neon_evm/bugs/test_storage_cell_zero.py

@@ -0,0 +1,86 @@
+import pytest
+from solana.keypair import Keypair
+from solana.transaction import Signature
+
+from integration.tests.neon_evm.utils.contract import deploy_contract
+from integration.tests.neon_evm.utils.neon_api_client import NeonApiClient
+from utils.accounts import EthAccounts
+from utils.evm_loader import EvmLoader
+from utils.helpers import wait_condition
+from utils.solana_client import SolanaClient
+from utils.types import Contract, Caller, TreasuryPool
+from utils.web3client import NeonChainWeb3Client
+
+
+@pytest.mark.parametrize(
+    "function_signature",
+    [
+        "saveZeroToVar",
+        "saveZeroToMapping",
+        "saveZeroToMappingCycle",
+    ],
+)
+class TestStorageCells:
+
+    def test_emulate_save_zero(
+            self,
+            operator_keypair: Keypair,
+            user_account: Caller,
+            evm_loader: EvmLoader,
+            treasury_pool: TreasuryPool,
+            neon_api_client: NeonApiClient,
+            sol_client: SolanaClient,
+            function_signature: str,
+    ):
+        contract: Contract = deploy_contract(
+            operator=operator_keypair,
+            user=user_account,
+            contract_file_name="issues/Ndev3234.sol",
+            evm_loader=evm_loader,
+            treasury_pool=treasury_pool,
+            contract_name="saveZeros",
+            version="0.8.12",
+        )
+
+        emulate_result = neon_api_client.emulate_contract_call(
+            sender=user_account.eth_address.hex(),
+            contract=contract.eth_address.hex(),
+            function_signature=function_signature + "()",
+        )
+
+        accounts_count = len(emulate_result["solana_accounts"])
+        assert accounts_count == 2, f"{accounts_count - 2} new account(s) created"
+
+    def test_save_zero(
+            self,
+            web3_client: NeonChainWeb3Client,
+            function_signature: str,
+            accounts: EthAccounts,
+            sol_client: SolanaClient,
+    ):
+        account = accounts[0]
+        contract, _ = web3_client.deploy_and_get_contract(
+            contract="issues/Ndev3234.sol",
+            version="0.8.12",
+            account=account,
+            contract_name="saveZeros",
+        )
+
+        raw_eth_tx = self.web3_client.make_raw_tx(from_=account)
+        instruction_tx = getattr(contract.functions, function_signature)().build_transaction(raw_eth_tx)
+        receipt = self.web3_client.send_transaction(account, instruction_tx)
+        assert receipt.status == 1
+        solana_tx_hash = web3_client.get_solana_trx_by_neon(receipt.transactionHash.hex())["result"][0]
+        solana_tx = wait_condition(
+            func_cond=lambda: sol_client.get_transaction(
+                tx_sig=Signature.from_string(solana_tx_hash),
+                max_supported_transaction_version=0,
+            ),
+            check_success=lambda tx: tx.value is not None,
+        )
+        if solana_tx.value.transaction.transaction.message.address_table_lookups:
+            alt = solana_tx.value.transaction.transaction.message.address_table_lookups
+            accounts_count = len(alt[0].writable_indexes) + len(alt[0].readonly_indexes)
+        else:
+            accounts_count = len(solana_tx.value.transaction.transaction.message.account_keys)
+        assert accounts_count == 9, f"{accounts_count - 9} new account(s) created"