Add Fuzz or Property Tests for Numeric Inputs #109
Description
Description:
Property-based or fuzz testing can uncover integer overflow, unexpected rounding, or invalid-state edge cases that hand-written tests miss. For example: calculate_split with very large total_amount or odd percentages; add_to_goal with amounts that could overflow current_amount; create_bill with boundary amounts or dates. This issue asks the team to evaluate adding property/fuzz tests (e.g. with proptest or quickcheck) for at least one contract and its numeric operations, or to document why it is not feasible (e.g. Soroban test env limitations, no_std, or seed stability) so that future contributors know the tradeoff.
Requirements
Evaluation: Determine whether proptest, quickcheck, or another property-test crate works in the Soroban test environment (no_std, custom env). If yes: add at least one property test (e.g. for calculate_split: for any total_amount and valid split percentages, the sum of returned amounts equals total_amount; or for add_to_goal: adding positive amounts never decreases balance). If no: add a short note in the test module or docs explaining that property tests are not run and that edge cases are covered by unit tests.
Scope: Focus on numeric-heavy functions: remittance_split calculate_split, savings_goals add_to_goal / withdraw_from_goal, bill_payments create_bill amounts, insurance create_policy amounts.
Acceptance Criteria
- At least one contract has a property or fuzz test for numeric behavior; or a documented explanation of why such tests are not included.
- No regression in existing unit tests; CI still passes.