Project Proposal: Create Hiero Ethereum Client Spec Project #249
Description
This proposal is to create a new project called hiero/hiero-ethereum-execution-spec-tests forking https://github.com/ethereum/execution-spec-tests to ensure Ethereum compatibility. The effort to adapt the client spec to Hiero has already been done, on a non hiero repository, that will be used for initializing this new repository.
Suggested name under Hiero
hiero-ledger/hiero-ethereum-execution-spec-tests
Supporters of the project
ferparishuertas
Project Description
The ethereum/execution-spec-tests repository serves as a comprehensive Python-based framework and collection of test cases designed to generate standardized test vectors (in JSON format) for Ethereum execution clients. These test fixtures verify the correct implementation of the Ethereum Execution Layer Specifications (EELS), covering state transitions, block validation, and EVM (Ethereum Virtual Machine) behaviors across various hard forks (e.g., Shanghai, Prague).
Being Hiero an Ethereum compatible chain, its key to ensure the compatibility and mantain the client spec execution and testing up to date, to the latest adopted upgrade/fork. As Hiero has a set of special functionalities, the upgrade calendar is not direclty binded to Ethereums schedule and also several EIPs have been intentionally not incorporated to Hiero (e.g. Blobs), the client spec for Hiero will include modifications that skip or adapt the existing tests to ensure compatibility. The Source code will be not 100% equal to the Ethereum project, enabling hiero to fork the exisitng repository.
Background
Ethereum's execution layer defines the core rules for transaction processing, smart contract execution, and state management, making it the foundational standard for Layer 1 (L1) blockchains. The execution-spec-tests framework emerged from the Ethereum community's need for reproducible, spec-aligned testing amid rapid evolution—such as the Berlin (2021), London (2021), and Shanghai (2023) hard forks—to prevent consensus divergences that could fragment the network. Developed under the STEEL (Specification, Testing, Execution Layer) initiative, it streamlines test generation by abstracting client-specific binaries, reducing manual effort and errors in verifying EIPs (Ethereum Improvement Proposals). This has been instrumental in maintaining interoperability across over 10 execution clients, powering tools like ethereum/hive for end-to-end network simulations.
For Hiero, an Ethereum L1-compatible chain, forking this repository is strategically essential to uphold seamless compatibility with the Ethereum ecosystem. As an L1, Hiero must mirror Ethereum's execution semantics to support EVM bytecode, ERC standards (e.g., ERC-20/721), and future upgrades without introducing friction for developers or users migrating from Ethereum mainnet. Forking allows the Hiero team to:
Initial Maintainers
@hiero-ledger/hiero-consensus-node-smart-contract-codeowners
@hiero-ledger/hiero-json-rpc-relay-maintainers
Initial Committers
@hiero-ledger/hiero-json-rpc-relay-committers