test(stf): add unit tests for processDepositRequest

[lodekeeper-z]

Summary

Unit tests for processDepositRequest (Electra deposit request processing).

Tests added:

• First request sets depositRequestsStartIndex — verifies UNSET → request index
• Subsequent request preserves start index — second request doesn't overwrite
• Pending deposit fields match request — amount and slot copied correctly
• Already-set start index is preserved — non-UNSET value not overwritten

Coverage:

• Both branches of the UNSET_DEPOSIT_REQUESTS_START_INDEX check
• PendingDeposit field correctness
• Append behavior on pendingDeposits list

🤖 Generated with AI assistance

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a comprehensive suite of unit tests for the processDepositRequest function, specifically targeting its behavior within the Electra fork. The tests ensure the correct initialization and preservation of the depositRequestsStartIndex, as well as the accurate mapping of deposit request fields to pending deposits, thereby enhancing the reliability and correctness of the state transition logic.

Highlights

• First request sets depositRequestsStartIndex: Verifies that when the depositRequestsStartIndex is UNSET, the first deposit request correctly initializes it to the request's index.
• Subsequent request preserves start index: Ensures that processing a second deposit request does not overwrite an already set depositRequestsStartIndex.
• Pending deposit fields match request: Confirms that the amount and slot fields of a pending deposit are accurately copied from the incoming deposit request.
• Already-set start index is preserved: Validates that if the depositRequestsStartIndex is already set to a non-UNSET value, it remains unchanged upon processing new deposit requests.

🧠 New Feature in Public Preview: You can now enable Memory to help Gemini Code Assist learn from your team's feedback. This makes future code reviews more consistent and personalized to your project's style. Click here to enable Memory in your admin console.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for GitHub and other Google products, sign up here.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This pull request introduces a suite of unit tests for the processDepositRequest function, specifically targeting the Electra fork logic. The tests verify the initialization and persistence of the depositRequestsStartIndex and the correct mapping of request fields to pending deposits. Review feedback suggests increasing assertion density in helper functions to comply with the project's style guide and expanding test coverage to verify all fields of the pending deposit, such as pubkey and signature, rather than just amount and slot.

[gemini-code-assist]

The style guide (lines 51, 55) mandates assertions on function arguments. This function is missing them. Please add an assertion to validate the index argument, for example, to ensure it's not a sentinel value.

    assert(index != c.UNSET_DEPOSIT_REQUESTS_START_INDEX);
    return DepositRequest{
        .pubkey = [_]u8{@as(u8, @intCast(index & 0xFF))} ** 48,
        .withdrawal_credentials = [_]u8{0x01} ++ [_]u8{0} ** 11 ++ [_]u8{0xAA} ** 20,
        .amount = 32_000_000_000,
        .signature = [_]u8{0} ** 96,
        .index = index,
    };

References

1. Assert all function arguments and return values, pre/postconditions and invariants. The assertion density of the code must average a minimum of two assertions per function. ^(link)

[lodekeeper-z]

This is a test-only helper — assertions on function arguments in the style guide are for production code paths, not test fixtures. The index value is always a literal in each test. Dismissing.

[lodekeeper-z]

This is a test-only helper — assertions on function arguments in the style guide are for production code paths, not test fixtures. The index value is always a literal in each test. Dismissing.

[gemini-code-assist]

This test is incomplete as it only verifies amount and slot. To ensure full correctness and prevent regressions, it should also verify that pubkey, withdrawal_credentials, and signature are copied correctly from the request to the PendingDeposit.

Also, it's better to compare against request.amount instead of a hardcoded value to make the test more resilient to changes in makeDepositRequest.

    // Verify all fields were copied correctly.
    const pubkey_view = try deposit.get("pubkey");
    var actual_pubkey: [48]u8 = undefined;
    _ = try pubkey_view.getAllInto(actual_pubkey[0..]);
    try testing.expectEqualSlices(u8, &request.pubkey, &actual_pubkey);

    const withdrawal_credentials_view = try deposit.get("withdrawal_credentials");
    var actual_withdrawal_credentials: [32]u8 = undefined;
    _ = try withdrawal_credentials_view.getAllInto(actual_withdrawal_credentials[0..]);
    try testing.expectEqualSlices(
        u8,
        &request.withdrawal_credentials,
        &actual_withdrawal_credentials,
    );

    const signature_view = try deposit.get("signature");
    var actual_signature: [96]u8 = undefined;
    _ = try signature_view.getAllInto(actual_signature[0..]);
    try testing.expectEqualSlices(u8, &request.signature, &actual_signature);

    const amount_view = try deposit.get("amount");
    try testing.expectEqual(request.amount, amount_view);

    const slot_view = try deposit.get("slot");
    const state_slot = try state.slot();
    try testing.expectEqual(state_slot, slot_view);

[lodekeeper-z]

Good point on field verification. I'll add pubkey, withdrawal_credentials, and signature checks using getAllInto, and reference request.amount instead of the hardcoded value. Pushing a fix.