Add tests for create_contract bounds (MAX_MILESTONES and MAX_TOTAL_ESCROW_STROOPS)

[mikewheeleer]

Description

create_contract enforces TooManyMilestones when milestone_amounts.len() > MAX_MILESTONES (10), InvalidMilestoneAmount for non-positive amounts or totals over MAX_TOTAL_ESCROW_STROOPS, and PotentialOverflow via safe_add_amounts. The orphaned test_bounds.rs covers some of this but is not compiled. Add wired tests for all bounds.

Requirements and context

• Scoped to TalentTrust escrow Soroban contract (contracts/escrow).
• Assert: exactly 10 milestones succeeds; 11 panics TooManyMilestones; zero/negative milestone panics InvalidMilestoneAmount; total over MAX_TOTAL_ESCROW_STROOPS panics; near-i128::MAX amounts panic PotentialOverflow.
• Assert InvalidParticipant when client == freelancer and EmptyMilestones for an empty vector.
• Acceptance: each guard in create_contract has a dedicated case.
• Must be secure, tested, and documented.

Suggested execution

• Fork the repo and create a branch:
  • git checkout -b test/create-contract-bounds
• Implement changes:
  • contracts/escrow/src/test/milestone_schedule.rs
  • Tests: contracts/escrow/src/test/milestone_schedule.rs
  • Docs: docs/escrow/milestone-validation.md
  • Include rustdoc/NatSpec-style doc comments on public functions
  • Validate security assumptions (auth, overflow, fail-closed state machine, storage TTL, fee accounting)

Test and commit

• Run tests: cargo test
• Cover edge cases (unauthorized callers, double release/refund, expired approvals, fee rounding, paused state)
• Include test output and security notes in the PR

Example commit message

test(escrow): cover create_contract bounds and overflow

Guidelines

• Minimum 95% test coverage on new/changed code
• Clear documentation
• Timeframe: 96 hours from assignment

[alexitsejames-cpu]

@alexitsejames-cpu has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hi can you please assign these issue to me

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[drips-wave]

Congratulations, @alexitsejames-cpu! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

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