test(tests): add BLOCKHASH genesis hash availability test

tests/frontier/opcodes/test_blockhash.py

@@ -0,0 +1,74 @@
+"""Tests for BLOCKHASH opcode."""
+
+import pytest
+
+from ethereum_test_tools import (
+    Account,
+    Alloc,
+    Block,
+    BlockchainTestFiller,
+    Storage,
+    Transaction,
+)
+from ethereum_test_tools import Opcodes as Op
+
+
+@pytest.mark.valid_from("Frontier")
+def test_genesis_hash_available(blockchain_test: BlockchainTestFiller, pre: Alloc):
+    """
+    Verify BLOCKHASH returns genesis and block 1 hashes.
+
+    Regression test: Blockchain test infrastructure must populate block hashes
+    before execution. Without this, BLOCKHASH returns 0, breaking dynamic
+    address computations like BLOCKHASH(0) | TIMESTAMP.
+
+    Tests both genesis (block 0) and first executed block (block 1) hash
+    insertion by calling the contract in block 2.
+
+    Bug context: revm blockchaintest runner wasn't inserting block_hashes,
+    causing failures in tests with BLOCKHASH-derived addresses.
+    """
+    storage = Storage()
+
+    # Store ISZERO(BLOCKHASH(0)) and ISZERO(BLOCKHASH(1))
+    # Both should be 0 (false) if hashes exist
+    code = Op.SSTORE(storage.store_next(0), Op.ISZERO(Op.BLOCKHASH(0))) + Op.SSTORE(
+        storage.store_next(0), Op.ISZERO(Op.BLOCKHASH(1))
+    )
+
+    contract = pre.deploy_contract(code=code)
+    sender = pre.fund_eoa()
+
+    blocks = [
+        Block(
+            txs=[
+                Transaction(
+                    sender=sender,
+                    to=contract,
+                    gas_limit=100_000,
+                    protected=False,
+                )
+            ]
+        ),
+        Block(
+            txs=[
+                Transaction(
+                    sender=sender,
+                    to=contract,
+                    gas_limit=100_000,
+                    protected=False,
+                )
+            ]
+        ),
+    ]
+
+    post = {
+        contract: Account(
+            storage={
+                0: 0,  # ISZERO(BLOCKHASH(0)) = 0 (genesis hash exists)
+                1: 0,  # ISZERO(BLOCKHASH(1)) = 0 (block 1 hash exists)
+            }
+        )
+    }
+
+    blockchain_test(pre=pre, post=post, blocks=blocks)