spitfire05/toy-payments-engine

toy-payments-engine

Usage

cargo run -- INPUT

or

./toy-payments-engine INPUT

where INPUT is the path to the CSV file with input.

Tests

Can be run by cargo test. They are divided in 3 groups:

• Unit tests - defined in respective modules.
• Functional tests - defined in tests/functional.rs - test the whole application with prepared data sets.
• User Interaction - defined in tests/ui.rs - test the "unhappy path" feedback for the user.

Notes, assumptions and considerations

• The input csv is processed one-row-at-a-time. This is to prevent excessive memory usage on big input sets.
• The type used to handle the transaction amounts is f64. In real application, probably something custom, less prone to rounding errors, should be used.
• Only deposit transactions can be disputed.
• "Locked" clients can not accept deposits nor withdrawals. They can, however, accept new disputes, resolves and chargebacks.
• The current implementation of Repository is not very multithread-friendly nor optimized, but it can be easily modified to be so by modifying clients field to be of type HashMap<u16, Mutex<Client>>, aquiring the lock in register_transaction method, and sharing the Repository object between threads via an Arc. This way we can aquire Mutex locks per client instead of on whole repository.