feat(tests): Add blob gas subtraction order tests

[spencer-tb]

🗒️ Description

Adds parameterized tests to ensure that the blob gas fee is subtracted from the sender's balance before a blob transaction is executed. Includes the case where the sender recieves funds before the blob tx is executed.

🔗 Related Issues

As requested by @marioevz: #385

✅ Checklist

• All: Set appropriate labels for the changes.
• All: Considered squashing commits to improve commit history.
• All: Added an entry to CHANGELOG.md.
• All: Considered updating the online docs in the ./docs/ directory.
• Tests: Included the type and version of evm t8n tool used to locally execute test cases: e.g., ref with commit hash or geth 1.13.1-stable-3f40e65.
• Tests: Ran mkdocs serve locally and verified the auto-generated docs for new tests in the Test Case Reference are correctly formatted.

[spencer-tb]

I initially tried to verify the balance values stored within the post state of the destination_account.

This was easy without the additional parameterization of the max_fee_per... fields.
You can find the following revision here: spencer-tb@4be8852
Within this the entire total account minimum fee, required to execute the tx was removed (incl. the blob gas fee) before executing the tx and contract code.

However when it came to using the max_fee_per... fields, I maybe spent a day trying to figure out the correct formula for the balance subtraction, as the amount subtracted is less than the value for the total account minimum fee.

Would you like me continue and add a check for the balance? Similarly sstore the return value of the call to send funds?

[marioevz]

I initially tried to verify the balance values stored within the post state of the destination_account.

This was easy without the additional parameterization of the max_fee_per... fields. You can find the following revision here: spencer-tb@4be8852 Within this the entire total account minimum fee, required to execute the tx was removed (incl. the blob gas fee) before executing the tx and contract code.

However when it came to using the max_fee_per... fields, I maybe spent a day trying to figure out the correct formula for the balance subtraction, as the amount subtracted is less than the value for the total account minimum fee.

Would you like me continue and add a check for the balance? Similarly sstore the return value of the call to send funds?

So if we try to check the stored balance, the balance should be zero only for cases where
a) tx.max_fee_per_gas == block.base_fee_per_gas
b) tx.max_fee_per_blob_gas == block.blob_base_fee_per_gas

both (a) and (b) are true, because if you check the validation steps in 1559 (which are very similar to 4844) https://eips.ethereum.org/EIPS/eip-1559, the formula for the minimum balance for the transaction to be intrinsically valid takes tx.max_fee_per_gas and tx.max_fee_per_blob_gas into account, whereas the actual balance subtraction, which happens right before the transaction execution, uses block.base_fee_per_gas and block.blob_base_fee_per_gas respectively.

So this is why we fund the account with the maximum amount it would have to pay in any block, because otherwise the transaction is invalid.

[marioevz]

Looks really good, just a few comments.

[marioevz]

To calculate the actual balance we can use a similar approach to function total_account_minimum_balance, but instead of calculating using tx_max_fee_per_blob_gas and tx_max_fee_per_gas, we use the actual blob base fee and normal base fee of the block (functions blob_gasprice and block_fee_per_gas pytest fixtures), and we subtract that from the minimum account balance.

[spencer-tb]

We now have the total_account_transactions_fee fixture within: b49c5b0 alongside the updates to the tests for the post state balance checks. Some small naming tweaks were made to the total_account_minimum_balance fixture.

Within: f226e54 I removed a duplicate fixture.

I am just working on adding the max_priority_fee_per_gas parameterization to the calculation.

[spencer-tb]

We should be a go now!

[marioevz]

Awesome! Thanks!