bug(fw): fix block header gasLimit value in post genesis blocks for…

… blockchain tests (#472)

* fix: use parent env's gas limit in current env #468

* fix(fw): update to include self gas limit.

* chore: add changelog.

---------

Co-authored-by: spencer-tb <spencer@spencertaylorbrown.uk>

docs/CHANGELOG.md

@@ -23,6 +23,7 @@ Test fixtures for use by clients are available for each release on the [Github r
 - 🐞 Fix bug that causes an exception during test collection because the fork parameter contains `None` ([#452](https://github.com/ethereum/execution-spec-tests/pull/452)).
 - ✨ The `_info` field in the test fixtures now contains a `hash` field, which is the hash of the test fixture, and a `hasher` script has been added which prints and performs calculations on top of the hashes of all fixtures (see `hasher -h`) ([#454](https://github.com/ethereum/execution-spec-tests/pull/454)).
 - ✨ Adds an optional `verify_sync` field to hive blockchain tests (EngineAPI). When set to true a second client attempts to sync to the first client that executed the tests.([#431](https://github.com/ethereum/execution-spec-tests/pull/431)).
+- 🐞 Fix manually setting the gas limit in the genesis test env for post genesis blocks in blockchain tests. ([#472](https://github.com/ethereum/execution-spec-tests/pull/472)).
 
 ### 🔧 EVM Tools
 

src/ethereum_test_tools/spec/blockchain/types.py

@@ -548,9 +548,7 @@ def set_environment(self, env: Environment) -> Environment:
         new_env.coinbase = (
             self.coinbase if self.coinbase is not None else environment_default.coinbase
         )
-        new_env.gas_limit = (
-            self.gas_limit if self.gas_limit is not None else environment_default.gas_limit
-        )
+        new_env.gas_limit = self.gas_limit or env.parent_gas_limit or environment_default.gas_limit
         if not isinstance(self.base_fee, Removable):
             new_env.base_fee = self.base_fee
         new_env.withdrawals = self.withdrawals