Why this matters now:
The project has proptest coverage for token arithmetic (added in #41), but zero fuzz coverage for the two contracts with more complex state machines: task-registry (task lifecycle, expiry boundary arithmetic, double-claim prevention) and reward-engine (multi-oracle, reward range math, cooldown arithmetic, cursor pagination). A formal audit requires demonstrable fuzz testing of security-critical paths. Adding proptest now creates the foundation auditors expect and will catch arithmetic and state-machine bugs before the audit begins.
Problem / What:
contracts/eco-token/src/token.rs has a proptest! block covering mint, transfer, and burn. Neither task-registry/src/registry.rs nor reward-engine/src/verification.rs have any property-based tests. Critical arithmetic paths that need fuzzing include:
create_task: arbitrary reward_amount, max_completions, expires_at values near boundariesextend_task_expiry: new_expires_at vs. current expires_at orderingset_reward_range + approve_proof: reward amounts near min, max, task budget- Cooldown arithmetic:
current_ledger.saturating_sub(last) near overflow/underflow
Key Challenges:
- Soroban's
Env::default() is not Send, which limits proptest's default test runner; use proptest_config(ProptestConfig::with_cases(N)) as done in eco-token.
- Property: "total_supply after N approve_proof calls == sum of all approved reward_amounts" — requires multi-step state setup.
- Property: "no sequence of valid calls leaves
task.completions > task.max_completions" — state machine invariant.
Acceptance Criteria:
task-registry has at least 3 proptest properties covering creation validation, expiry boundary, and completion count invariants.reward-engine has at least 3 proptest properties covering reward range enforcement, total_paid accumulation, and cooldown boundary.- All proptest cases use
ProptestConfig::with_cases(20) minimum.
cargo test --workspace passes including new proptest cases.
Relevant files/functions:
contracts/task-registry/src/registry.rs — test modulecontracts/reward-engine/src/verification.rs — test modulecontracts/eco-token/src/token.rs — reference implementation of proptest pattern
Out of scope: Integration fuzz, mutation testing, changing production code.
Why this matters now:
The project has proptest coverage for token arithmetic (added in #41), but zero fuzz coverage for the two contracts with more complex state machines:
task-registry(task lifecycle, expiry boundary arithmetic, double-claim prevention) andreward-engine(multi-oracle, reward range math, cooldown arithmetic, cursor pagination). A formal audit requires demonstrable fuzz testing of security-critical paths. Adding proptest now creates the foundation auditors expect and will catch arithmetic and state-machine bugs before the audit begins.Problem / What:
contracts/eco-token/src/token.rshas aproptest!block covering mint, transfer, and burn. Neithertask-registry/src/registry.rsnorreward-engine/src/verification.rshave any property-based tests. Critical arithmetic paths that need fuzzing include:create_task: arbitraryreward_amount,max_completions,expires_atvalues near boundariesextend_task_expiry:new_expires_atvs.current expires_atorderingset_reward_range+approve_proof: reward amounts nearmin,max, task budgetcurrent_ledger.saturating_sub(last)near overflow/underflowKey Challenges:
Env::default()is notSend, which limits proptest's default test runner; useproptest_config(ProptestConfig::with_cases(N))as done in eco-token.task.completions > task.max_completions" — state machine invariant.Acceptance Criteria:
task-registryhas at least 3 proptest properties covering creation validation, expiry boundary, and completion count invariants.reward-enginehas at least 3 proptest properties covering reward range enforcement, total_paid accumulation, and cooldown boundary.ProptestConfig::with_cases(20)minimum.cargo test --workspacepasses including new proptest cases.Relevant files/functions:
contracts/task-registry/src/registry.rs— test modulecontracts/reward-engine/src/verification.rs— test modulecontracts/eco-token/src/token.rs— reference implementation of proptest patternOut of scope: Integration fuzz, mutation testing, changing production code.