feat(tests): Add tests for ecadd/ecmul/ecpairing constant gas repricing

docs/CHANGELOG.md

@@ -29,6 +29,7 @@ Test fixtures for use by clients are available for each release on the [Github r
 - ✨ Expand cases to test *CALL opcodes causing OOG ([#1703](https://github.com/ethereum/execution-specs/pull/1703)).
 - ✨ Add tests for `modexp` and `ripemd` precompiled contracts ([#1691](https://github.com/ethereum/execution-specs/pull/1691)).
 - ✨ Add `ecrecover` precompile tests originating form `evmone` unittests ([#1685](https://github.com/ethereum/execution-specs/pull/1685)).
+- ✨ Add tests for ecadd/ecmul/ecpairing constant gas repricing ([#1738](https://github.com/ethereum/execution-specs/pull/1738)).
 
 ## [v5.3.0](https://github.com/ethereum/execution-spec-tests/releases/tag/v5.3.0) - 2025-10-09
 

tests/frontier/precompiles/test_bn254.py

@@ -0,0 +1,62 @@
+"""Tests ecadd/ecmul/ecpairing precompiled contracts."""
+
+import pytest
+from execution_testing import (
+    Account,
+    Alloc,
+    Environment,
+    StateTestFiller,
+    Transaction,
+)
+from execution_testing.base_types.base_types import Address
+from execution_testing.forks import Byzantium, Istanbul
+from execution_testing.forks.helpers import Fork
+from execution_testing.vm import Opcodes as Op
+
+
+@pytest.mark.valid_from("Byzantium")
+@pytest.mark.parametrize(
+    "address,gas_pre_istanbul,gas_post_istanbul",
+    [
+        pytest.param(0x06, 500, 150, id="ecadd"),
+        pytest.param(0x07, 40_000, 6000, id="ecmul"),
+        pytest.param(0x08, 100_000, 45_000, id="ecpairing"),
+    ],
+)
+@pytest.mark.parametrize("enough_gas", [True, False])
+def test_bn254_precompiles_gascosts(
+    state_test: StateTestFiller,
+    pre: Alloc,
+    fork: Fork,
+    address: Address,
+    gas_pre_istanbul: int,
+    gas_post_istanbul: int,
+    enough_gas: bool,
+) -> None:
+    """
+    Tests the constant gas behavior of `ecadd/ecmul/ecpairing` precompiled
+    contract.
+    """
+    env = Environment()
+    if fork < Istanbul:
+        gas = gas_pre_istanbul
+    else:
+        gas = gas_post_istanbul
+    if not enough_gas:
+        gas -= 1
+
+    account = pre.deploy_contract(
+        code=Op.SSTORE(0, Op.CALL(gas=gas, address=address)),
+        storage={0: 0xDEADBEEF},
+    )
+
+    tx = Transaction(
+        to=account,
+        sender=pre.fund_eoa(),
+        gas_limit=100_0000,
+        protected=fork >= Byzantium,
+    )
+
+    post = {account: Account(storage={0: 1 if enough_gas else 0})}
+
+    state_test(env=env, pre=pre, post=post, tx=tx)