A coding test project implementing a mock ATM controller for Bear Robotics Inc.
Run the included script.py file.
General controller flow is given as the following:
Insert Card => Enter PIN Number => Select Account => See Balance/Deposit/Withdraw
To strictly follow the flow given, we make the following assumption:
- Single PIN number is tied to the inserted card and all accounts
accessible via the card.
- Although it may be possible to have different PINS tied to different accounts and have the entered PIN associated with a specific account, this needlessly complicates the flow and would be pretty bad for user experience as this would mean entering a PIN number before selecting an account.
The following is a rough overview of the flow:
Note that there are some details missing on how actions are handled.
A single session implements the flow described above.
- Once a new session is initiated, the ATM starts to wait for a card to be insered.
- Following the general flow, the session ends when the card is ejected from the ATM and is retrieved.
All information within a session should be ephemeral and be lost once the session ends. The included script is a simple loop of running sessions.
- Without an ATM API and/or a bank API, a sensible implementation of a controller is rather hard, since we do not know how much error handling should be delegated to other components.
- The implementation provided here is pretty lousy in terms of security. Initial PIN validation should serve only as initial authentication and subsequent transactions should use some sort of token scheme or encryption based on first authentication.
- General flow and display of information have been simplified greatly for convienence in terms of implementation.