forks: Implement fork operators, remove is_fork (#367)

* ethereum_test_forks: implement fork operators, remove `is_fork`

* changelog

docs/CHANGELOG.md

@@ -13,6 +13,7 @@ Test fixtures for use by clients are available for each release on the [Github r
 - ✨ Add a `--single-fixture-per-file` flag to generate one fixture JSON file per test case ([#331](https://github.com/ethereum/execution-spec-tests/pull/331)).
 - 🔀 Rename test fixtures names to match the corresponding pytest node ID as generated using `fill` ([#342](https://github.com/ethereum/execution-spec-tests/pull/342)).
 - 💥 Replace "=" with "_" in pytest node ids and test fixture names ([#342](https://github.com/ethereum/execution-spec-tests/pull/342)).
+- ✨ Fork objects used to write tests can now be compared using the `>`, `>=`, `<`, `<=` operators, to check for a fork being newer than, newer than or equal, older than, older than or equal, respectively when compared against other fork ([#367](https://github.com/ethereum/execution-spec-tests/pull/367))
 
 ### 🔧 EVM Tools
 

src/ethereum_test_forks/__init__.py

@@ -32,7 +32,6 @@
     get_development_forks,
     get_forks,
     get_transition_forks,
-    is_fork,
     transition_fork_from_to,
     transition_fork_to,
 )
@@ -64,7 +63,6 @@
     "get_deployed_forks",
     "get_development_forks",
     "get_forks",
-    "is_fork",
     "transition_fork_from_to",
     "transition_fork_to",
 ]

src/ethereum_test_forks/base_fork.py

@@ -36,6 +36,30 @@ def __repr__(cls) -> str:
         """
         return cls.name()
 
+    def __gt__(cls, other: "BaseForkMeta") -> bool:
+        """
+        Compare if a fork is newer than some other fork.
+        """
+        return cls != other and other.__subclasscheck__(cls)
+
+    def __ge__(cls, other: "BaseForkMeta") -> bool:
+        """
+        Compare if a fork is newer than or equal to some other fork.
+        """
+        return other.__subclasscheck__(cls)
+
+    def __lt__(cls, other: "BaseForkMeta") -> bool:
+        """
+        Compare if a fork is older than some other fork.
+        """
+        return cls != other and cls.__subclasscheck__(other)
+
+    def __le__(cls, other: "BaseForkMeta") -> bool:
+        """
+        Compare if a fork is older than or equal to some other fork.
+        """
+        return cls.__subclasscheck__(other)
+
 
 class BaseFork(ABC, metaclass=BaseForkMeta):
     """

src/ethereum_test_forks/helpers.py

@@ -135,18 +135,3 @@ def forks_from(fork: Fork, deployed_only: bool = True) -> List[Fork]:
     else:
         latest_fork = get_forks()[-1]
     return forks_from_until(fork, latest_fork)
-
-
-def is_fork(fork: Fork, which: Fork) -> bool:
-    """
-    Returns `True` if `fork` is `which` or beyond, `False otherwise.
-    """
-    prev_fork = fork
-
-    while prev_fork != BaseFork:
-        if prev_fork == which:
-            return True
-
-        prev_fork = prev_fork.__base__
-
-    return False

src/ethereum_test_forks/tests/test_forks.py

@@ -13,7 +13,6 @@
     get_deployed_forks,
     get_development_forks,
     get_forks,
-    is_fork,
     transition_fork_from_to,
     transition_fork_to,
 )
@@ -94,9 +93,38 @@ def test_forks():
     assert cast(Fork, MergeToShanghaiAtTime15k).header_withdrawals_required(0, 15_000) is True
     assert cast(Fork, MergeToShanghaiAtTime15k).header_withdrawals_required() is True
 
-    assert is_fork(Berlin, Berlin) is True
-    assert is_fork(London, Berlin) is True
-    assert is_fork(Berlin, Merge) is False
+    # Test fork comparison
+    assert Merge > Berlin
+    assert not Berlin > Merge
+    assert Berlin < Merge
+    assert not Merge < Berlin
+
+    assert Merge >= Berlin
+    assert not Berlin >= Merge
+    assert Berlin <= Merge
+    assert not Merge <= Berlin
+
+    assert London > Berlin
+    assert not Berlin > London
+    assert Berlin < London
+    assert not London < Berlin
+
+    assert London >= Berlin
+    assert not Berlin >= London
+    assert Berlin <= London
+    assert not London <= Berlin
+
+    assert Berlin >= Berlin
+    assert Berlin <= Berlin
+    assert not Berlin > Berlin
+    assert not Berlin < Berlin
+
+    fork = Berlin
+    assert fork >= Berlin
+    assert fork <= Berlin
+    assert not fork > Berlin
+    assert not fork < Berlin
+    assert fork == Berlin
 
 
 def test_get_forks():  # noqa: D103

tests/berlin/eip2930_access_list/test_acl.py

@@ -4,7 +4,7 @@
 
 import pytest
 
-from ethereum_test_forks import Fork, London, is_fork
+from ethereum_test_forks import Fork, London
 from ethereum_test_tools import AccessList, Account, Environment
 from ethereum_test_tools import Opcodes as Op
 from ethereum_test_tools import StateTestFiller, Transaction
@@ -60,7 +60,7 @@ def test_access_list(state_test: StateTestFiller, fork: Fork):
             nonce=1,
         ),
         "0x2adc25665018aa1fe0e6bc666dac8fc2697ff9ba": Account(
-            balance=0x1BC16D674EC80000 if is_fork(fork, London) else 0x1BC16D674ECB26CE,
+            balance=0x1BC16D674EC80000 if fork >= London else 0x1BC16D674ECB26CE,
         ),
         "0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b": Account(
             balance=0x2CD931,

tests/cancun/eip6780_selfdestruct/test_selfdestruct.py

@@ -11,7 +11,7 @@
 import pytest
 from ethereum.crypto.hash import keccak256
 
-from ethereum_test_forks import Cancun, Fork, is_fork
+from ethereum_test_forks import Cancun, Fork
 from ethereum_test_tools import (
     Account,
     Block,
@@ -50,7 +50,7 @@
 @pytest.fixture
 def eip_enabled(fork: Fork) -> bool:
     """Whether the EIP is enabled or not."""
-    return is_fork(fork, SELFDESTRUCT_ENABLE_FORK)
+    return fork >= SELFDESTRUCT_ENABLE_FORK
 
 
 @pytest.fixture

tests/shanghai/eip3651_warm_coinbase/test_warm_coinbase.py

@@ -10,7 +10,7 @@
 
 import pytest
 
-from ethereum_test_forks import Shanghai, is_fork
+from ethereum_test_forks import Shanghai
 from ethereum_test_tools import (
     Account,
     CodeGasMeasure,
@@ -117,7 +117,7 @@ def test_warm_coinbase_call_out_of_gas(
 
     post = {}
 
-    if use_sufficient_gas and is_fork(fork=fork, which=Shanghai):
+    if use_sufficient_gas and fork >= Shanghai:
         post[caller_address] = Account(
             storage={
                 # On shanghai and beyond, calls with only 100 gas to
@@ -244,7 +244,7 @@ def test_warm_coinbase_gas_usage(state_test, fork, opcode, code_gas_measure):
         measure_address: Account(code=code_gas_measure, balance=1000000000000000000000),
     }
 
-    if is_fork(fork, Shanghai):
+    if fork >= Shanghai:
         expected_gas = GAS_REQUIRED_CALL_WARM_ACCOUNT  # Warm account access cost after EIP-3651
     else:
         expected_gas = 2600  # Cold account access cost before EIP-3651

whitelist.txt

@@ -235,6 +235,7 @@ stExample
 str
 streetsidesoftware
 subcall
+subclasscheck
 subdirectories
 subdirectory
 subgraph