new(tests): Add tests for OOGing in EXP variable gas

Author: pdobacz

src/ethereum_test_forks/forks/forks.py

@@ -116,7 +116,7 @@ def gas_costs(cls, *, block_number: int = 0, timestamp: int = 0) -> GasCosts:
             G_CALL_STIPEND=2_300,
             G_NEW_ACCOUNT=25_000,
             G_EXP=10,
-            G_EXP_BYTE=50,
+            G_EXP_BYTE=10,
             G_MEMORY=3,
             G_TX_DATA_ZERO=4,
             G_TX_DATA_NON_ZERO=68,
@@ -814,12 +814,22 @@ class Tangerine(DAOFork, ignore=True):
 
 
 class SpuriousDragon(Tangerine, ignore=True):
-    """SpuriousDragon fork (EIP-155, EIP-158)."""
+    """SpuriousDragon fork (EIP-155, EIP-158, EIP-160)."""
+
+    @classmethod
+    def gas_costs(cls, *, block_number: int = 0, timestamp: int = 0) -> GasCosts:
+        """
+        On SpuriousDragon, EXP byte gas cost is increased to 50.
+        """
+        return replace(
+            super(SpuriousDragon, cls).gas_costs(block_number=block_number, timestamp=timestamp),
+            G_EXP_BYTE=50,  # https://eips.ethereum.org/EIPS/eip-160
+        )
 
     pass
 
 
-class Byzantium(Homestead):
+class Byzantium(SpuriousDragon):
     """Byzantium fork."""
 
     @classmethod

tests/frontier/opcodes/test_all_opcodes.py

@@ -284,6 +284,7 @@ def test_constant_gas(
         + (code_increment_counter if opcode == Op.CREATE2 else Bytecode())
     )
     gas_test(
+        fork,
         state_test,
         env,
         pre,

tests/frontier/opcodes/test_exp.py

@@ -0,0 +1,61 @@
+"""
+Test EXP opcode.
+"""
+
+import pytest
+
+from ethereum_test_base_types.base_types import ZeroPaddedHexNumber
+from ethereum_test_forks import Fork
+from ethereum_test_tools import (
+    Alloc,
+    Environment,
+    StateTestFiller,
+)
+from ethereum_test_vm import Opcodes as Op
+from tests.unscheduled.eip7692_eof_v1.gas_test import gas_test
+
+REFERENCE_SPEC_GIT_PATH = "N/A"
+REFERENCE_SPEC_VERSION = "N/A"
+
+
+def exp_gas(fork: Fork, exponent: int) -> int:
+    """Calculate gas cost for EXP opcode given the exponent."""
+    byte_len = (exponent.bit_length() + 7) // 8
+    return fork.gas_costs().G_EXP + fork.gas_costs().G_EXP_BYTE * byte_len
+
+
+@pytest.mark.valid_from("Berlin")
+@pytest.mark.parametrize("a", [0, 1, pytest.param(2**256 - 1, id="a2to256minus1")])
+@pytest.mark.parametrize(
+    "exponent",
+    [
+        0,
+        1,
+        2,
+        1023,
+        1024,
+        pytest.param(2**255, id="exponent2to255"),
+        pytest.param(2**256 - 1, id="exponent2to256minus1"),
+    ],
+)
+def test_gas(
+    state_test: StateTestFiller, pre: Alloc, a: int, exponent: int, fork: Fork, env: Environment
+) -> None:
+    """Test that EXP gas works as expected."""
+    warm_gas = exp_gas(fork, exponent)
+
+    if cap := fork.transaction_gas_limit_cap():
+        env.gas_limit = ZeroPaddedHexNumber(cap)
+
+    gas_test(
+        fork,
+        state_test,
+        env,
+        pre,
+        setup_code=Op.PUSH32(exponent) + Op.PUSH32(a),
+        subject_code=Op.EXP,
+        tear_down_code=Op.STOP,
+        cold_gas=warm_gas,
+        warm_gas=warm_gas,
+        eof=False,
+    )

tests/unscheduled/eip7692_eof_v1/eip7069_extcall/test_gas.py

@@ -134,6 +134,7 @@ def test_ext_calls_gas(
     )
     cost_memory_bytes = fork.memory_expansion_gas_calculator()
     gas_test(
+        fork,
         state_test,
         state_env,
         pre,
@@ -153,6 +154,7 @@ def test_ext_calls_gas(
 def test_transfer_gas_is_cleared(
     state_test: StateTestFiller,
     pre: Alloc,
+    fork: Fork,
     state_env: Environment,
     opcode: Op,
     value: int,
@@ -174,6 +176,7 @@ def test_transfer_gas_is_cleared(
     push_gas = (4 if opcode == Op.EXTCALL else 3) * 3
 
     gas_test(
+        fork,
         state_test,
         state_env,
         pre,
@@ -197,6 +200,7 @@ def test_transfer_gas_is_cleared(
 def test_late_account_create(
     state_test: StateTestFiller,
     pre: Alloc,
+    fork: Fork,
     state_env: Environment,
     opcode: Op,
 ) -> None:
@@ -207,6 +211,7 @@ def test_late_account_create(
     empty_address = Address(0xDECAFC0DE)
 
     gas_test(
+        fork,
         state_test,
         state_env,
         pre,

tests/unscheduled/eip7692_eof_v1/eip7620_eof_create/test_gas.py

@@ -138,6 +138,7 @@ def test_eofcreate_gas(
     )
     cost_memory_bytes = fork.memory_expansion_gas_calculator()
     gas_test(
+        fork,
         state_test,
         Environment(),
         pre,

tests/unscheduled/eip7692_eof_v1/gas_test.py

@@ -3,6 +3,8 @@
 import itertools
 
 from ethereum_test_base_types.base_types import Address
+from ethereum_test_forks.forks.forks import Berlin
+from ethereum_test_forks.helpers import Fork
 from ethereum_test_tools import Account, Alloc, Environment, StateTestFiller, Transaction
 from ethereum_test_types.eof.v1 import Container, Section
 from ethereum_test_vm import Bytecode, EVMCodeType
@@ -24,6 +26,7 @@
 
 
 def gas_test(
+    fork: Fork,
     state_test: StateTestFiller,
     env: Environment,
     pre: Alloc,
@@ -48,6 +51,9 @@ def gas_test(
     test, and MUST NOT have any side-effects which persist across message
     calls, and in particular, any effects on the gas usage of `subject_code`.
     """
+    if fork < Berlin:
+        raise ValueError("Gas tests before Berlin are not supported due to CALL gas changes")
+
     if cold_gas <= 0:
         raise ValueError(f"Target gas allocations (cold_gas) must be > 0, got {cold_gas}")
     if warm_gas is None: