[feat] Generate Utreexo integration tests

[m-kus]

Context

We are porting (a subset of) rustreexo to Cairo and we also need to adopt their testing suite to ensure correctness.

Task

Generate a Cairo file with unit test stubs so that each stub contains test case data (initial roots, leaves to be added/deleted, proofs, expected roots). We will add the actual execution later.

Step 1: pre-process files from https://github.com/mit-dci/rustreexo/tree/main/test_values by converting them to a flat list of identical test cases (removing unnecessary info like cached nodes and adding missing data like expected roots).

Step 2: code generate Cairo unit tests using the processed data.

You'll end up having two Python scripts that do the job.

Implementation notes

Expected processed file format:

[{
    "type": "<test type: add,verify,delete,update>",
    "roots": [],
    "numleaves": 0,
    "expected_roots": [],
    "expected_numleaves": 0,
    "leaves_to_add": [],
    "leaves_to_del": [],
    "proof": { "targets": [], "hashes": [] },
}]

Expected Cairo unit test:

#[test]
fn test_add_0() {
    let test_case = UtreexoTestCase {
        type: UtreexoTestType::Add,
        roots: [],
        ...
    };
}

Note that depending on the test type some data might be omitted.

Test data pre-processing:

• test_cases.json/insertion_tests: leaf preimages have to be transformed into hashes, test type "add", see https://github.com/mit-dci/rustreexo/blob/6a8fe53fa545df8f1a30733fa6ca9f7b0077d051/src/accumulator/stump.rs#L502
• test_cases.json/proof_tests: target preimages have to be transformed into hashes, test type "verify", see https://github.com/mit-dci/rustreexo/blob/6a8fe53fa545df8f1a30733fa6ca9f7b0077d051/src/accumulator/proof.rs#L1327
• test_cases.json/deletion_tests: leaf_preimages have to be transformed into hashes, test type "delete", see https://github.com/mit-dci/rustreexo/blob/6a8fe53fa545df8f1a30733fa6ca9f7b0077d051/src/accumulator/stump.rs#L465
• update_data_tests.json: you'll need to compute expected roots by running rust tests and printing Stump state at the end of the test, test type "update", see https://github.com/mit-dci/rustreexo/blob/6a8fe53fa545df8f1a30733fa6ca9f7b0077d051/src/accumulator/stump.rs#L335
• cached_proof_tests.json: added leaves preimages have to be transformed into hashes, cache data has to be discarded, test type "update", see https://github.com/mit-dci/rustreexo/blob/6a8fe53fa545df8f1a30733fa6ca9f7b0077d051/src/accumulator/proof.rs#L850

Write files to the following locations (one for each test type):

• Processed json files: packages/utreexo/tests/data/*.json
• Generated Cairo tests: packages/utreexo/tests/*.cairo

Place definitions of UtreexoTestCase and UtreexoTestType to packages/utreexo/tests/lib.cairo