Add v0.3.1 backwards compatibility tests for StorableBuilder and KeyObfuscator

[tnull]

We recently made some changes to StorableBuilder and KeyObfuscator. This just adds two upgrade tests that ensure backwards compatibility with Storables/keys that have been serialized/obfuscated on v0.3.1.

Co-authored by Claude AI.

[ldk-reviews-bot]

👋 Thanks for assigning @tankyleo as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

[ldk-reviews-bot]

🔔 1st Reminder

Hey @tankyleo! This PR has been waiting for your review.
Please take a look when you have a chance. If you're unable to review, please let us know so we can find another reviewer.

[tankyleo]

Reproduced v031_serialized and v031_obfuscated_key on v0.31 as in the snippet below.

snippet

use vss_client::util::key_obfuscator::KeyObfuscator;
use vss_client::util::storable_builder::{TestEntropyProvider, StorableBuilder, EntropySource};
use prost::Message;

fn main() {
    let obfuscate = KeyObfuscator::new([0xAB; 32]);
    let obfuscated = obfuscate.obfuscate("my_storage_key_v031_compat");
    let v031_obfuscated_key = "nxrixRQPGawY+a9JFLThii0RgeADtEdSjh2YDgpZhBKOuw6GKr5UAIIwsQCathJlZsmuSku+RGB1/JuxFUMQGoAwa+M8tg";
    assert_eq!(obfuscated, v031_obfuscated_key);

    let test_entropy_provider = TestEntropyProvider;
    let mut data_key = [0u8; 32];
    test_entropy_provider.fill_bytes(&mut data_key);

    let storable_builder = StorableBuilder::new(data_key, TestEntropyProvider);
    let object = storable_builder.build(b"backward_compat_test_data".to_vec(), 42);
    let mut buf = Vec::new();
    object.encode(&mut buf).unwrap();

    let v031_serialized = vec![
            0x0a, 0x1d, 0x32, 0x19, 0xe9, 0xfb, 0x45, 0xd7, 0x42, 0xf5, 0x6c, 0x40, 0x1b, 0x74,
            0x13, 0xe7, 0xae, 0x07, 0xfd, 0x81, 0xe1, 0x43, 0x3a, 0xf2, 0x86, 0x3c, 0xe8, 0x8f,
            0x01, 0xf8, 0x6c, 0x12, 0x32, 0x0a, 0x10, 0x43, 0x68, 0x61, 0x43, 0x68, 0x61, 0x32,
            0x30, 0x50, 0x6f, 0x6c, 0x79, 0x31, 0x33, 0x30, 0x35, 0x12, 0x0c, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x1a, 0x10, 0x87, 0x16, 0x35,
            0x02, 0x26, 0x1e, 0x30, 0xec, 0x7c, 0xf1, 0x4b, 0x79, 0x70, 0xa2, 0x41, 0x16,
    ];

    assert_eq!(buf, v031_serialized);
}

[tankyleo]

All tests pass on my machine with rustc 1.90.0, including the two v031 compat tests introduced here.