feat(tests,tools): [WIP] initial invalid BAL tests

Author: fselmo

src/ethereum_test_forks/forks/forks.py

@@ -1810,6 +1810,11 @@ def max_blobs_per_block(cls, block_number: int = 0, timestamp: int = 0) -> int:
 class Amsterdam(Osaka):
     """Amsterdam fork."""
 
+    @classmethod
+    def header_bal_hash_required(cls, block_number: int = 0, timestamp: int = 0) -> bool:
+        """From Amsterdam, header must contain block access list hash (EIP-7928)."""
+        return block_number > 0  # Not required in genesis block
+
     @classmethod
     def is_deployed(cls) -> bool:
         """Return True if this fork is deployed."""

src/ethereum_test_specs/blockchain.py

@@ -208,6 +208,10 @@ class Block(Header):
     An RLP modifying header which values would be used to override the ones
     returned by the `ethereum_clis.TransitionTool`.
     """
+    expected_block_access_list: BlockAccessListExpectation | None = None
+    """
+    If set, the block access list will be verified and potentially corrupted for invalid tests.
+    """
     exception: BLOCK_EXCEPTION_TYPE = None
     """
     If set, the block is expected to be rejected by the client.
@@ -624,6 +628,14 @@ def generate_block_data(
             header = block.rlp_modifier.apply(header)
             header.fork = fork  # Deleted during `apply` because `exclude=True`
 
+        # Process block access list - apply transformer if present for invalid tests
+        bal = transition_tool_output.result.block_access_list
+        if block.expected_block_access_list is not None and bal is not None:
+            # Use to_fixture_bal to validate and potentially transform the BAL
+            bal = block.expected_block_access_list.to_fixture_bal(bal)
+            # Don't update the header hash - leave it as the hash of the correct BAL
+            # This creates a mismatch that should cause the block to be rejected
+
         built_block = BuiltBlock(
             header=header,
             alloc=transition_tool_output.alloc,
@@ -636,7 +648,7 @@ def generate_block_data(
             expected_exception=block.exception,
             engine_api_error_code=block.engine_api_error_code,
             fork=fork,
-            block_access_list=transition_tool_output.result.block_access_list,
+            block_access_list=bal,
         )
 
         try:
@@ -648,14 +660,20 @@ def generate_block_data(
                 and block.rlp_modifier is None
                 and block.requests is None
                 and not block.skip_exception_verification
+                and not (
+                    block.expected_block_access_list is not None
+                    and block.expected_block_access_list.modifier is not None
+                )
             ):
                 # Only verify block level exception if:
-                # - No transaction exception was raised, because these are not reported as block
-                #   exceptions.
-                # - No RLP modifier was specified, because the modifier is what normally
-                #   produces the block exception.
-                # - No requests were specified, because modified requests are also what normally
-                #   produces the block exception.
+                # - No transaction exception was raised, because these are not
+                #   reported as block exceptions.
+                # - No RLP modifier was specified, because the modifier is what
+                #   normally produces the block exception.
+                # - No requests were specified, because modified requests are also
+                #   what normally produces the block exception.
+                # - No BAL modifier was specified, because modified BAL also
+                #   produces block exceptions.
                 built_block.verify_block_exception(
                     transition_tool_exceptions_reliable=t8n.exception_mapper.reliable,
                 )
@@ -740,11 +758,7 @@ def make_fixture(
             )
             fixture_blocks.append(built_block.get_fixture_block())
 
-            # Verify block access list if expected
-            if self.expected_block_access_list is not None:
-                self.verify_block_access_list(
-                    built_block.block_access_list, self.expected_block_access_list
-                )
+            # BAL verification already done in to_fixture_bal() if expected_block_access_list set
 
             if block.exception is None:
                 # Update env, alloc and last block hash for the next block.

src/ethereum_test_types/block_access_list.py renamed to src/ethereum_test_types/block_access_list/__init__.py

@@ -5,7 +5,7 @@
 these are simple data classes that can be composed together.
 """
 
-from typing import Any, ClassVar, List
+from typing import Any, Callable, ClassVar, List, Optional
 
 import ethereum_rlp as eth_rlp
 from pydantic import Field
@@ -23,6 +23,20 @@
 from ethereum_test_base_types.serialization import to_serializable_element
 
 
+def compose(
+    *modifiers: Callable[["BlockAccessList"], "BlockAccessList"],
+) -> Callable[["BlockAccessList"], "BlockAccessList"]:
+    """Compose multiple modifiers into a single modifier."""
+
+    def composed(bal: BlockAccessList) -> BlockAccessList:
+        result = bal
+        for modifier in modifiers:
+            result = modifier(result)
+        return result
+
+    return composed
+
+
 class BalNonceChange(CamelModel, RLPSerializable):
     """Represents a nonce change in the block access list."""
 
@@ -155,6 +169,60 @@ class BlockAccessListExpectation(CamelModel):
         default_factory=list, description="Expected account changes to verify"
     )
 
+    modifier: Optional[Callable[["BlockAccessList"], "BlockAccessList"]] = Field(
+        None,
+        exclude=True,
+        description="Optional modifier to modify the BAL for invalid tests",
+    )
+
+    def modify(
+        self, *modifiers: Callable[["BlockAccessList"], "BlockAccessList"]
+    ) -> "BlockAccessListExpectation":
+        """
+        Create a new expectation with a modifier for invalid test cases.
+
+        Args:
+            modifiers: One or more functions that take and return a BlockAccessList
+
+        Returns:
+            A new BlockAccessListExpectation instance with the modifiers applied
+
+        Example:
+            from ethereum_test_types.block_access_list.modifiers import remove_nonces
+
+            expectation = BlockAccessListExpectation(
+                account_changes=[...]
+            ).modify(remove_nonces(alice))
+
+        """
+        new_instance = self.model_copy(deep=True)
+        new_instance.modifier = compose(*modifiers)
+        return new_instance
+
+    def to_fixture_bal(self, t8n_bal: "BlockAccessList") -> "BlockAccessList":
+        """
+        Convert t8n BAL to fixture BAL, optionally applying transformations.
+
+        1. First validates expectations are met (if any)
+        2. Then applies modifier if specified (for invalid tests)
+
+        Args:
+            t8n_bal: The BlockAccessList from t8n tool
+
+        Returns:
+            The potentially transformed BlockAccessList for the fixture
+
+        """
+        # Only validate if we have expectations
+        if self.account_changes:
+            self.verify_against(t8n_bal)
+
+        # Apply modifier if present (for invalid tests)
+        if self.modifier:
+            return self.modifier(t8n_bal)
+
+        return t8n_bal
+
     def verify_against(self, actual_bal: "BlockAccessList") -> None:
         """
         Verify that the actual BAL from the client matches this expected BAL.
@@ -320,3 +388,17 @@ def _compare_change_lists(self, field_name: str, expected: List, actual: List) -
                 raise AssertionError(msg)
 
         return True
+
+
+__all__ = [
+    # Core models
+    "BlockAccessList",
+    "BlockAccessListExpectation",
+    # Change types
+    "BalAccountChange",
+    "BalNonceChange",
+    "BalBalanceChange",
+    "BalCodeChange",
+    "BalStorageChange",
+    "BalStorageSlot",
+]