test: add property tests for settlement quorum logic

[Jay989810]

Closes #194

Description

This PR introduces property-based (fuzz-style) unit tests for the settlement approval and quorum execution logic using proptest. Rather than relying solely on static example-based tests, these property tests sweep randomized combinations of signer weight allocations, quorum thresholds, and approval subsets to ensure off-by-one, boundary, and threshold calculation bugs do not occur.

Proposed Changes

• Dependency Configuration:
  • Added proptest = "1.4" to [dev-dependencies] in contracts/settlement/Cargo.toml and COMEBACKHERE-contracts/contracts/treasury/Cargo.toml.
  • Updated contracts/Cargo.toml workspace members to include "settlement".
• Settlement Contract (comebackhere-settlement):
  • Added prop_settlement_quorum_logic in contracts/settlement/src/lib.rs.
  • Validates that accumulated signer approval weight incrementally matches expected sums across random signer weights (1..100) and threshold limits (1..500).
• Treasury Contract (comebackhere-treasury):
  • Added prop_treasury_settlement_quorum_execution in COMEBACKHERE-contracts/contracts/treasury/src/integration_settlement_multisig.rs.
  • Asserts that execute_settlement succeeds (Ok(())) if and only if accumulated weight >= threshold, and fails with TreasuryError::InsufficientApprovals if accumulated weight < threshold.

---

Test Output

1. comebackhere-settlement Test Suite

$ cargo test --package comebackhere-settlement

running 7 tests
test tests::test_approve_not_found ... ok
test tests::test_approve_increments_weight_and_returns_threshold ... ok
test tests::test_approve_unauthorized_signer ... ok
test tests::test_approve_not_pending ... ok
test tests::test_approve_already_approved ... ok
test tests::test_multiple_signers_accumulate_weight ... ok
test tests::prop_settlement_quorum_logic ... ok

test result: ok. 7 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.91s

[drips-wave]

@Jay989810 Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits