refactor(tests): use pytest parametrize to reduce code duplication in BloatNet tests (#2242)

Replace duplicate test functions with parametrized versions to avoid repetitive
code. Each test now accepts a `balance_first` parameter that controls the order
of operations, eliminating the need for separate `_extcodesize_balance`,
`_extcodecopy_balance`, and `_extcodehash_balance` variants.

Changes:
- Add @pytest.mark.parametrize to test_bloatnet_balance_extcodesize,
  test_bloatnet_balance_extcodecopy, and test_bloatnet_balance_extcodehash
- Each test now generates two variants via parametrization with descriptive IDs
  (e.g., "balance_extcodesize" and "extcodesize_balance")
- Extract operation sequences into variables and conditionally compose them
  based on balance_first parameter
- Remove test_bloatnet_extcodesize_balance, test_bloatnet_extcodecopy_balance,
  and test_bloatnet_extcodehash_balance (now covered by parametrization)

This reduces the file from 793 lines to 462 lines while maintaining the same
test coverage (6 tests total: 3 test functions × 2 parametrization values).

To run specific parameter variants, use the -k flag:
  fill -k "balance_extcodesize" tests/benchmark/bloatnet/test_multi_opcode.py
  fill -k "extcodesize_balance" tests/benchmark/bloatnet/test_multi_opcode.py

Author: CPerezz

tests/benchmark/stateful/bloatnet/test_multi_opcode.py

@@ -49,12 +49,18 @@
 #   4. Attack rapidly accesses all contracts, stressing client's state handling
 
 
+@pytest.mark.parametrize(
+    "balance_first",
+    [True, False],
+    ids=["balance_extcodesize", "extcodesize_balance"],
+)
 @pytest.mark.valid_from("Prague")
 def test_bloatnet_balance_extcodesize(
     blockchain_test: BlockchainTestFiller,
     pre: Alloc,
     fork: Fork,
     gas_benchmark_value: int,
+    balance_first: bool,
 ):
     """
     BloatNet test using BALANCE + EXTCODESIZE with "on-the-fly" CREATE2
@@ -63,7 +69,7 @@ def test_bloatnet_balance_extcodesize(
     This test:
     1. Assumes contracts are already deployed via the factory (salt 0 to N-1)
     2. Generates CREATE2 addresses dynamically during execution
-    3. Calls BALANCE (cold) then EXTCODESIZE (warm) on each
+    3. Calls BALANCE and EXTCODESIZE (order controlled by balance_first param)
     4. Maximizes cache eviction by accessing many contracts
     """
     gas_costs = fork.gas_costs()
@@ -75,11 +81,11 @@ def test_bloatnet_balance_extcodesize(
     cost_per_contract = (
         gas_costs.G_KECCAK_256  # SHA3 static cost for address generation (30)
         + gas_costs.G_KECCAK_256_WORD * 3  # SHA3 dynamic cost (85 bytes = 3 words * 6)
-        + gas_costs.G_COLD_ACCOUNT_ACCESS  # Cold BALANCE (2600)
-        + gas_costs.G_BASE  # POP balance (2)
-        + gas_costs.G_WARM_ACCOUNT_ACCESS  # Warm EXTCODESIZE (100)
-        + gas_costs.G_BASE  # POP code size (2)
-        + gas_costs.G_BASE  # DUP1 before BALANCE (3)
+        + gas_costs.G_COLD_ACCOUNT_ACCESS  # Cold access (2600)
+        + gas_costs.G_BASE  # POP first result (2)
+        + gas_costs.G_WARM_ACCOUNT_ACCESS  # Warm access (100)
+        + gas_costs.G_BASE  # POP second result (2)
+        + gas_costs.G_BASE  # DUP1 before first op (3)
         + gas_costs.G_VERY_LOW * 4  # PUSH1 operations (4 * 3)
         + gas_costs.G_LOW  # MLOAD for salt (3)
         + gas_costs.G_VERY_LOW  # ADD for increment (3)
@@ -108,6 +114,13 @@ def test_bloatnet_balance_extcodesize(
         f"Factory storage will be checked during execution."
     )
 
+    # Define operations that differ based on parameter
+    balance_op = Op.POP(Op.BALANCE)
+    extcodesize_op = Op.POP(Op.EXTCODESIZE)
+    benchmark_ops = (
+        (balance_op + extcodesize_op) if balance_first else (extcodesize_op + balance_op)
+    )
+
     # Build attack contract that reads config from factory and performs attack
     attack_code = (
         # Call getConfig() on factory to get num_deployed and init_code_hash
@@ -143,9 +156,8 @@ def test_bloatnet_balance_extcodesize(
                 # Generate CREATE2 addr: keccak256(0xFF+factory+salt+hash)
                 Op.SHA3(11, 85)  # Generate CREATE2 address from memory[11:96]
                 # The address is now on the stack
-                + Op.DUP1  # Duplicate for EXTCODESIZE
-                + Op.POP(Op.BALANCE)  # Cold access
-                + Op.POP(Op.EXTCODESIZE)  # Warm access
+                + Op.DUP1  # Duplicate for second operation
+                + benchmark_ops  # Execute operations in specified order
                 # Increment salt for next iteration
                 + Op.MSTORE(32, Op.ADD(Op.MLOAD(32), 1))  # Increment and store salt
             ),
@@ -177,12 +189,18 @@ def test_bloatnet_balance_extcodesize(
     )
 
 
+@pytest.mark.parametrize(
+    "balance_first",
+    [True, False],
+    ids=["balance_extcodecopy", "extcodecopy_balance"],
+)
 @pytest.mark.valid_from("Prague")
 def test_bloatnet_balance_extcodecopy(
     blockchain_test: BlockchainTestFiller,
     pre: Alloc,
     fork: Fork,
     gas_benchmark_value: int,
+    balance_first: bool,
 ):
     """
     BloatNet test using BALANCE + EXTCODECOPY with on-the-fly CREATE2
@@ -191,8 +209,8 @@ def test_bloatnet_balance_extcodecopy(
     This test forces actual bytecode reads from disk by:
     1. Assumes contracts are already deployed via the factory
     2. Generating CREATE2 addresses dynamically during execution
-    3. Using BALANCE (cold) to warm the account
-    4. Using EXTCODECOPY (warm) to read 1 byte from the END of the bytecode
+    3. Using BALANCE and EXTCODECOPY (order controlled by balance_first param)
+    4. Reading 1 byte from the END of the bytecode to force full contract load
     """
     gas_costs = fork.gas_costs()
     max_contract_size = fork.max_code_size()
@@ -204,16 +222,16 @@ def test_bloatnet_balance_extcodecopy(
     cost_per_contract = (
         gas_costs.G_KECCAK_256  # SHA3 static cost for address generation (30)
         + gas_costs.G_KECCAK_256_WORD * 3  # SHA3 dynamic cost (85 bytes = 3 words * 6)
-        + gas_costs.G_COLD_ACCOUNT_ACCESS  # Cold BALANCE (2600)
-        + gas_costs.G_BASE  # POP balance (2)
-        + gas_costs.G_WARM_ACCOUNT_ACCESS  # Warm EXTCODECOPY base (100)
+        + gas_costs.G_COLD_ACCOUNT_ACCESS  # Cold access (2600)
+        + gas_costs.G_BASE  # POP first result (2)
+        + gas_costs.G_WARM_ACCOUNT_ACCESS  # Warm access base (100)
         + gas_costs.G_COPY * 1  # Copy cost for 1 byte (3)
-        + gas_costs.G_BASE * 2  # DUP1 before BALANCE, DUP4 for address (6)
+        + gas_costs.G_BASE * 2  # DUP1 before first op, DUP4 for address (6)
         + gas_costs.G_VERY_LOW * 8  # PUSH operations (8 * 3 = 24)
         + gas_costs.G_LOW * 2  # MLOAD for salt twice (6)
         + gas_costs.G_VERY_LOW * 2  # ADD operations (6)
         + gas_costs.G_LOW  # MSTORE salt back (3)
-        + gas_costs.G_BASE  # POP after EXTCODECOPY (2)
+        + gas_costs.G_BASE  # POP after second op (2)
         + 10  # While loop overhead
     )
 
@@ -238,6 +256,20 @@ def test_bloatnet_balance_extcodecopy(
         f"Factory storage will be checked during execution."
     )
 
+    # Define operations that differ based on parameter
+    balance_op = Op.POP(Op.BALANCE)
+    extcodecopy_op = (
+        Op.PUSH1(1)  # size (1 byte)
+        + Op.PUSH2(max_contract_size - 1)  # code offset (last byte)
+        + Op.ADD(Op.MLOAD(32), 96)  # unique memory offset
+        + Op.DUP4  # address (duplicated earlier)
+        + Op.EXTCODECOPY
+        + Op.POP  # clean up address
+    )
+    benchmark_ops = (
+        (balance_op + extcodecopy_op) if balance_first else (extcodecopy_op + balance_op)
+    )
+
     # Build attack contract that reads config from factory and performs attack
     attack_code = (
         # Call getConfig() on factory to get num_deployed and init_code_hash
@@ -274,16 +306,7 @@ def test_bloatnet_balance_extcodecopy(
                 Op.SHA3(11, 85)  # Generate CREATE2 address from memory[11:96]
                 # The address is now on the stack
                 + Op.DUP1  # Duplicate for later operations
-                + Op.POP(Op.BALANCE)  # Cold access
-                # EXTCODECOPY(addr, mem_offset, last_byte_offset, 1)
-                # Read the LAST byte to force full contract load
-                + Op.PUSH1(1)  # size (1 byte)
-                + Op.PUSH2(max_contract_size - 1)  # code offset (last byte)
-                # Use salt as memory offset to avoid overlap
-                + Op.ADD(Op.MLOAD(32), 96)  # Add base memory offset for unique position
-                + Op.DUP4  # address (duplicated earlier)
-                + Op.EXTCODECOPY
-                + Op.POP  # Clean up address
+                + benchmark_ops  # Execute operations in specified order
                 # Increment salt for next iteration
                 + Op.MSTORE(32, Op.ADD(Op.MLOAD(32), 1))  # Increment and store salt
             ),
@@ -313,3 +336,132 @@ def test_bloatnet_balance_extcodecopy(
         blocks=[Block(txs=[attack_tx])],
         post=post,
     )
+
+
+@pytest.mark.parametrize(
+    "balance_first",
+    [True, False],
+    ids=["balance_extcodehash", "extcodehash_balance"],
+)
+@pytest.mark.valid_from("Prague")
+def test_bloatnet_balance_extcodehash(
+    blockchain_test: BlockchainTestFiller,
+    pre: Alloc,
+    fork: Fork,
+    gas_benchmark_value: int,
+    balance_first: bool,
+):
+    """
+    BloatNet test using BALANCE + EXTCODEHASH with on-the-fly CREATE2
+    address generation.
+
+    This test:
+    1. Assumes contracts are already deployed via the factory
+    2. Generates CREATE2 addresses dynamically during execution
+    3. Calls BALANCE and EXTCODEHASH (order controlled by balance_first param)
+    4. Forces client to compute code hash for 24KB bytecode
+    """
+    gas_costs = fork.gas_costs()
+
+    # Calculate gas costs
+    intrinsic_gas = fork.transaction_intrinsic_cost_calculator()(calldata=b"")
+
+    # Cost per contract access with CREATE2 address generation
+    cost_per_contract = (
+        gas_costs.G_KECCAK_256  # SHA3 static cost for address generation (30)
+        + gas_costs.G_KECCAK_256_WORD * 3  # SHA3 dynamic cost (85 bytes = 3 words * 6)
+        + gas_costs.G_COLD_ACCOUNT_ACCESS  # Cold access (2600)
+        + gas_costs.G_BASE  # POP first result (2)
+        + gas_costs.G_WARM_ACCOUNT_ACCESS  # Warm access (100)
+        + gas_costs.G_BASE  # POP second result (2)
+        + gas_costs.G_BASE  # DUP1 before first op (3)
+        + gas_costs.G_VERY_LOW * 4  # PUSH1 operations (4 * 3)
+        + gas_costs.G_LOW  # MLOAD for salt (3)
+        + gas_costs.G_VERY_LOW  # ADD for increment (3)
+        + gas_costs.G_LOW  # MSTORE salt back (3)
+        + 10  # While loop overhead
+    )
+
+    # Calculate how many contracts to access based on available gas
+    available_gas = gas_benchmark_value - intrinsic_gas - 1000  # Reserve for cleanup
+    contracts_needed = int(available_gas // cost_per_contract)
+
+    # Deploy factory using stub contract
+    factory_address = pre.deploy_contract(
+        code=Bytecode(),
+        stub="bloatnet_factory",
+    )
+
+    # Log test requirements
+    print(
+        f"Test needs {contracts_needed} contracts for "
+        f"{gas_benchmark_value / 1_000_000:.1f}M gas. "
+        f"Factory storage will be checked during execution."
+    )
+
+    # Define operations that differ based on parameter
+    balance_op = Op.POP(Op.BALANCE)
+    extcodehash_op = Op.POP(Op.EXTCODEHASH)
+    benchmark_ops = (
+        (balance_op + extcodehash_op) if balance_first else (extcodehash_op + balance_op)
+    )
+
+    # Build attack contract that reads config from factory and performs attack
+    attack_code = (
+        # Call getConfig() on factory to get num_deployed and init_code_hash
+        Op.STATICCALL(
+            gas=Op.GAS,
+            address=factory_address,
+            args_offset=0,
+            args_size=0,
+            ret_offset=96,
+            ret_size=64,
+        )
+        # Check if call succeeded
+        + Op.ISZERO
+        + Op.PUSH2(0x1000)  # Jump to error handler if failed
+        + Op.JUMPI
+        # Load results from memory
+        + Op.MLOAD(96)  # Load num_deployed_contracts
+        + Op.MLOAD(128)  # Load init_code_hash
+        # Setup memory for CREATE2 address generation
+        + Op.MSTORE(0, factory_address)
+        + Op.MSTORE8(11, 0xFF)
+        + Op.MSTORE(32, 0)  # Initial salt
+        + Op.PUSH1(64)
+        + Op.MSTORE  # Store init_code_hash
+        # Main attack loop
+        + While(
+            body=(
+                # Generate CREATE2 address
+                Op.SHA3(11, 85)
+                + Op.DUP1  # Duplicate for second operation
+                + benchmark_ops  # Execute operations in specified order
+                # Increment salt
+                + Op.MSTORE(32, Op.ADD(Op.MLOAD(32), 1))
+            ),
+            condition=Op.DUP1 + Op.PUSH1(1) + Op.SWAP1 + Op.SUB + Op.DUP1 + Op.ISZERO + Op.ISZERO,
+        )
+        + Op.POP  # Clean up counter
+    )
+
+    # Deploy attack contract
+    attack_address = pre.deploy_contract(code=attack_code)
+
+    # Run the attack
+    attack_tx = Transaction(
+        to=attack_address,
+        gas_limit=gas_benchmark_value,
+        sender=pre.fund_eoa(),
+    )
+
+    # Post-state
+    post = {
+        attack_address: Account(storage={}),
+    }
+
+    blockchain_test(
+        pre=pre,
+        blocks=[Block(txs=[attack_tx])],
+        post=post,
+    )