refactor(contract): factor out shared gen_authenticated_participants helper

[pbeza]

Closes #3650

[claude]

PR title type suggestion: This PR refactors code to use a shared helper, so the type prefix should be refactor: instead of test:.

Suggested title: refactor(contract): factor out shared gen_authenticated_participants helper

[claude]

Pull request overview

Factors out the per-test setup helpers that were duplicated across foreign_chain_rpc.rs, domain.rs, and verifier_votes.rs into a single shared gen_authenticated_participants helper in crates/contract/src/primitives/test_utils.rs. Pure test-side refactor — no production code touched, no behavior changes beyond consolidation.

Changes:

• New gen_authenticated_participants(n) in test_utils.rs that builds n participants and pre-authenticates each before any storage-backed state is written (the ordering invariant from the original foreign_chain_rpc.rs helper is preserved in the doc comment).
• Removes the three local helpers (setup/setup_participants) and their now-redundant VMContextBuilder / testing_env! imports.
• Each call site swaps to gen_authenticated_participants(...).

Reviewed changes

Per-file summary

File	Description
crates/contract/src/primitives/test_utils.rs	Adds the shared helper, plus AuthenticatedParticipantId and near_sdk::{test_utils::VMContextBuilder, testing_env} imports.
crates/contract/src/foreign_chain_rpc.rs	Drops local setup, swaps every call site to the shared helper, drops now-unused imports.
crates/contract/src/primitives/domain.rs	Drops local setup_participants, swaps every call site to the shared helper, drops now-unused imports.
crates/contract/src/tee/verifier_votes.rs	Drops local setup, setup_votes uses the shared helper.

Findings

No blocking issues.

Non-blocking (nits, follow-ups, suggestions):

• crates/contract/src/primitives/domain.rs:498 — Subtle behavior change worth flagging: the removed setup_participants previously did participants.insert(account_id, info).unwrap() (panic on duplicate); the new helper delegates to gen_participants, which silently swallows insert errors with let _ = participants.insert(...) at test_utils.rs:145. With 12-char random lowercase account IDs the collision probability is effectively zero in practice, so this is fine, but the inconsistency between gen_participants (silent) and the rest of the codebase (unwrap) is a latent footgun. Consider hardening gen_participants itself to .expect("test setup: duplicate participant account id") in a follow-up — out of scope for this PR.
• crates/contract/src/tee/tee_state.rs:1505,1549 — Two tests still inline the same VMContextBuilder + testing_env! + AuthenticatedParticipantId::new pattern, but only authenticate a subset of participants (2 of 5, 1 of 3). They don't fit gen_authenticated_participants's all-or-nothing shape, so leaving them out is reasonable; flagging only so future readers know it was a conscious scope choice.
• crates/contract/src/primitives/test_utils.rs:150-153 — Nice doc comment that captures the why (the testing_env! ordering invariant). No change requested — calling it out as a good example for similar future helpers.

✅ Approved

[Copilot]

Pull request overview

This PR reduces duplication across mpc-contract unit tests by extracting a shared helper that generates a participant set and pre-authenticates each participant, then updates several test modules to use it.

Changes:

• Added gen_authenticated_participants(n) to the shared contract test utilities.
• Replaced locally-defined “setup/authenticate participants” helpers in multiple test modules with the shared helper.
• Simplified test-only imports now that per-module authentication loops are removed.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
crates/contract/src/tee/verifier_votes.rs	Replaces local participant-auth setup with shared gen_authenticated_participants.
crates/contract/src/primitives/test_utils.rs	Introduces gen_authenticated_participants helper for reuse across tests.
crates/contract/src/primitives/domain.rs	Removes duplicated test setup helper; uses shared authenticated-participant generator.
crates/contract/src/foreign_chain_rpc.rs	Removes duplicated test setup helper; uses shared authenticated-participant generator.

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[claude]

PR title type suggestion: This PR modifies source code files, not test files only. Since you're factoring out a shared helper across multiple source modules, the type prefix should probably be refactor: instead of test:.

Suggested title: refactor(contract): factor out shared gen_authenticated_participants helper

[gilcu3]

Thank you!

[netrome]

Thanks!