Add test coverage that the upgrade entrypoint is admin-gated and emits the upgraded event even while paused

[mikewheeleer]

Test the upgrade auth gate and its deliberate paused-state exception

Description

upgrade in src/lib.rs is admin-gated, emits an upgraded event with the new WASM hash, and deliberately skips the pause gate so a paused router can still be patched. The doc comment reasons about this trade-off, but there is no test asserting (a) a non-admin caller is rejected and (b) an upgrade still proceeds and emits its event while the router is paused. This issue adds that coverage, including a real round-trip upgrade to a second WASM that preserves pair state.

Requirements and context

• Repository scope: StableRoute-Org/Stableroute-contracts only.
• Assert a non-admin caller cannot call upgrade.
• Assert the upgraded event is emitted carrying the new hash.
• Assert an upgrade succeeds while is_paused() is true (the documented exception).
• Use the Soroban test util pattern for registering a second contract WASM / hash so the upgrade actually swaps code and pair registrations survive.
• Distinct from the issues-1 "add a contract upgrade entrypoint" feature item — that builds upgrade; this issue verifies its auth and paused-exception behaviour.

Suggested execution

• Fork the repo and create a branch
• git checkout -b test/contracts-upgrade-auth-and-paused-coverage
• Implement changes
  • Write code in: src/lib.rs — no production change expected.
  • Write comprehensive tests in: src/lib.rs (inline #[cfg(test)] mod test) — cover non-admin rejection, the upgraded event, the paused-state exception, and state survival across the upgrade.
  • Add documentation: none required beyond test doc comments.
  • Include NatSpec-style doc comments (///) on each new test, matching the existing style in lib.rs.
  • Validate security assumptions: only admin upgrades; paused exception does not become an escalation path.
• Test and commit

Test and commit

• Run cargo fmt --all -- --check, cargo build, and cargo test.
• Cover edge cases: non-admin rejection, event emission, upgrade while paused, and pair state preserved post-upgrade.
• Include the full cargo test output in the PR description.

Example commit message

test: cover upgrade admin gating, upgraded event, and paused-state exception

Guidelines

• Minimum 95 percent test coverage for impacted modules.
• Clear, reviewer-focused documentation.
• Timeframe: 96 hours.

Community & contribution rewards

• 💬 Join the StableRoute community on Discord for questions, reviews, and faster merges: https://discord.gg/37aCpusvx
• ⭐ This is a GrantFox OSS / Official Campaign task and may be rewarded. When your PR is merged you'll be prompted to rate the project — if this issue and the maintainers helped you ship, we'd be grateful for a 5-star rating. Clear questions in Discord and tidy, well-tested PRs are the fastest path to a merge and a reward.

[gloskull]

Hi, I’d love to work on this issue. I have 4 years of experience across backend, frontend, full-stack, and smart contract development. I understand the task clearly and can deliver a clean, efficient, well-tested solution on time, with strong focus on code quality and maintainability. My PR will be submitted in under 10 hours.