feat(specs,fixtures,tests): New Spec/Fixture type: ConfigSpec

src/ethereum_test_fixtures/__init__.py

@@ -3,6 +3,7 @@
 from .base import BaseFixture, FixtureFormat, LabeledFixtureFormat
 from .blockchain import BlockchainEngineFixture, BlockchainFixture, BlockchainFixtureCommon
 from .collector import FixtureCollector, TestInfo
+from .config import ConfigFixture
 from .consume import FixtureConsumer
 from .eof import EOFFixture
 from .state import StateFixture
@@ -13,6 +14,7 @@
     "BlockchainEngineFixture",
     "BlockchainFixture",
     "BlockchainFixtureCommon",
+    "ConfigFixture",
     "EOFFixture",
     "FixtureCollector",
     "FixtureConsumer",

src/ethereum_test_fixtures/config.py

@@ -0,0 +1,58 @@
+"""Definitions for configuration tests fixtures."""
+
+import hashlib
+import json
+from functools import cached_property
+from typing import ClassVar
+
+from pydantic import computed_field
+
+from ethereum_test_base_types import Hash
+from ethereum_test_forks import ForkConfig
+
+from .base import BaseFixture
+
+
+class ConfigFixture(BaseFixture):
+    """Represents a configuration test fixture."""
+
+    fork: str
+    """
+    Fork of the network the fixture is for.
+
+    Must be excluded from the hash computation and it's for reference only.
+    """
+
+    network_name: str
+    """Name of the network the fixture is for."""
+
+    config: ForkConfig
+    """Configuration for the test."""
+
+    format_name: ClassVar[str] = "config_test"
+    description: ClassVar[str] = "Tests that generate a config test fixture."
+
+    @computed_field(alias="hash")  # type: ignore[misc]
+    @cached_property
+    def config_hash(self) -> Hash:
+        """
+        Compute the hash of the configuration.
+
+        This hash must be used to validate the configuration for a given network.
+
+        All fields are included in the hash computation except for the `hash` field itself,
+        the `network_name` and the `fork`.
+
+        The keys are sorted in lexicographic order before computing the hash.
+
+        If a field's value is `null`, its key and value are excluded from the hash computation.
+
+        The hash used is SHA-256.
+        """
+        json_obj = self.config.model_dump(mode="json", by_alias=True, exclude_none=True)
+        json_str = json.dumps(json_obj, sort_keys=True, separators=(",", ":"))
+        return Hash(hashlib.sha256(json_str.encode("utf-8")).digest())
+
+    def get_fork(self) -> str | None:
+        """Return fork of the fixture as a string."""
+        return self.fork

src/ethereum_test_forks/__init__.py

@@ -1,6 +1,7 @@
 """Ethereum test fork definitions."""
 
 from .base_fork import Fork, ForkAttribute
+from .config import ForkConfig
 from .forks.forks import (
     ArrowGlacier,
     Berlin,
@@ -54,6 +55,7 @@
     "Byzantium",
     "Constantinople",
     "ConstantinopleFix",
+    "ForkConfig",
     "Frontier",
     "GrayGlacier",
     "Homestead",

src/ethereum_test_forks/base_fork.py

@@ -10,6 +10,7 @@
 from ethereum_test_vm import EVMCodeType, Opcodes
 
 from .base_decorators import prefer_transition_to_method
+from .config import ForkConfig
 from .gas_costs import GasCosts
 
 
@@ -506,6 +507,12 @@ def fork_at(cls, block_number: int = 0, timestamp: int = 0) -> Type["BaseFork"]:
         """
         return cls
 
+    @classmethod
+    @abstractmethod
+    def config(cls, *, chain_id: int) -> ForkConfig:
+        """Return the configuration for the fork."""
+        pass
+
     @classmethod
     @abstractmethod
     def transition_tool_name(cls, block_number: int = 0, timestamp: int = 0) -> str:

src/ethereum_test_forks/config.py

@@ -0,0 +1,45 @@
+"""Definition for the configuration of a client in a given fork."""
+
+from ethereum_test_base_types import Address, CamelModel, ForkBlobSchedule
+
+
+class ForkConfig(CamelModel):
+    """Represents a configuration test fixture."""
+
+    chain_id: int
+    """
+    ID of the network this config is for.
+    """
+
+    homestead_block: int | None = None
+    dao_fork_block: int | None = None
+    dao_fork_support: bool | None = None
+
+    # EIP150 implements the Gas price changes (/~https://github.com/ethereum/EIPs/issues/150)
+    eip_150_block: int | None = None
+    eip_155_block: int | None = None
+    eip_158_block: int | None = None
+
+    byzantium_block: int | None = None
+    constantinople_block: int | None = None
+    petersburg_block: int | None = None
+    istanbul_block: int | None = None
+    muir_glacier_block: int | None = None
+    berlin_block: int | None = None
+    london_block: int | None = None
+    arrow_glacier_block: int | None = None
+    gray_glacier_block: int | None = None
+    merge_netsplit_block: int | None = None
+
+    # Fork scheduling was switched from blocks to timestamps here
+
+    shanghai_time: int | None = None
+    cancun_time: int | None = None
+    prague_time: int | None = None
+    osaka_time: int | None = None
+
+    terminal_total_difficulty: int | None = None
+
+    deposit_contract_address: Address | None = None
+
+    blob_schedule: ForkBlobSchedule | None = None