Cross-contract mocking test coverage

[ibrahimmosouf-png]

Cross-contract mocking test coverage

Labels: testing, priority/medium
Difficulty: Medium · Effort: M
Backlog slot: 65

Problem Statement

Existing tests run against Env::default() and the in-process token stubs (StellarAssetClient). Production cross-contract calls — real RPC, real auth frames, real event ordering — aren't unit-tested for behaviour, only for shape.

Why it Matters

• A token::Client::new call against an actual deployed token can fail in ways the stub never reproduces (e.g. balance cache lag, expired trustline, missing auth).
• Production regressions are caught by users, not by tests.

Expected Outcome

1. Introduce a MockTokenClient that records assertions (calls, balances, transfers) and lets tests inject failures.
2. Apply to release_milestone, claim_refund, donate paths where token transfers occur.
3. Add property tests that mutate the mock state and assert the contract reads.

Acceptance Criteria

• New mock used in ≥ 3 existing test files with no regression.
• All cross-contract call sites have a corresponding mocked test.

Files Likely Affected

• New: crates/testkit/src/mock_token.rs
• campaign/src/test/*

Dependencies

Issue #29 (E2E harness).

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[OluRemiFour]

Hi Maintainer,
Interested in working on this issue. I'll implement the requested changes and ensure everything is properly tested before submission.

Payout wallet (Stellar): GALHFNUOYOY4S5CNRK7OI7NKS7UNWYGSJII2POQ6XQKWMUVLKZ2SAWMP GrantFox OSS campaign — smart escrow payout on merge.

[Senorespecial]

i would love to work on this issue, please assign.

[grantfox-oss]

🦊 GrantFox — @Senorespecial has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #152)
2. Your PR will be reviewed by the OrbitChainLabs maintainers

Good luck! Track your progress on GrantFox.