account_balance format

[qperrot]

Describe the bug (observed vs expected behavior)

When calling /account_balance?address= it returns me an array of 3 int (ex: array[34, 7834, 984]). It should be low and high like for cairo, but it turns out the array returned by /account_balance consists of 32-bit parts of the number.

Not reproducible on testnet

• [ ] This issue is only present on Devnet and cannot be reproduced on the alpha-sepolia testnet (check the box if true).

Devnet version

• I am using Devnet version: latest
• [x] This happens with a dockerized Devnet (check the box if true).
• This does not appear on the following Devnet version:

[FabijanC]

@marioiordanov perhaps we should have made amount have type String. It was discussed here: https://github.com/0xSpaceShard/starknet-devnet-rs/pull/394#discussion_r1538928072. Rationale for using the String type: it's also used in e.g. /predeployed_accounts, and we don't have to force our users to do BigUint deserialization on their end.

Unfortunately the tests I wrote only load the amount using BigUint deserialization. And on creating the response the value is serialized from BigUint directly, so the fact that it gets converted to an array of u32 values was never discovered. I'll improve the tests.