# The ATM challenge ## Ruby basics - ATM Challenge ### Learning experience * Review fundamentals learned in the prep course * Learn about Ruby classes, modules, methods and attributes * Learn about unit testing with RSpec and the benefits of writing automated tests * Learn about naming standards * Learn about using double, class\_double and instance\_double * Learn about debugging and common techniques * Work with user stories * Learning how to pair program and work in a group ### The challenge Our client is a financial institution that wants to allow its customers to withdraw funds from their accounts using an Automatic Teller Machine (ATM). They have turned to us for a prototype of a system with limited functionality. Our job is to write a simple Ruby program that can be run in the Interactive Ruby Shell (IRB). **You will be working with your Coach and your peers to get started with using RSpec as a testing framework an with implementing your code.** ### Scope The following objectives must be met: * An ATM machine can hold up to $1000 * Withdrawal can be cleared only if * The ATM holds enough funds * The amount is divisible by 5 * the person attempting the withdrawal provides a valid ATM card * Valid pin and expire date * Card status must be active (Not report stolen or lost) * the person attempting the withdrawal has sufficient funds in his account * There are only $5, $10 and $20 bills in the ATM. Withdrawals for amounts not divisible by 5 must be rejected. * Upon a successful withdrawal the system should return a receipt with information about the date, amount and bills that was dispatched. (The receipt should be presented in the form of a Hash #### Example output ```ruby # Message on successful withdrawal { status: true, message: 'success', date: '2016-01-30', amount: 35, bills: [20,10,5]} # Error message - wrong pin { status: false, message: 'wrong pin', date: '2016-01-30'} # Error message - expired card { status: false, message: 'card expired', date: '2016-01-30'} ``` ## Tips and Tricks * Don't overdo it. Keep your implementation as simple as possible. * Test your code - both manually in IRB but, most importantly with automated tests. * You have to examine all tests ***before*** you write your production code. See tests as a blueprint for your implementation. * **Run one test at the time to avoid a massive output in your terminal.** Disable `it` blocks by adding an `x` before (as in `xit "Should..." do`) * Make sure to **commit often** and that you switch roles (driver/navigator) often. This is a good time to read the [Naming Standards](https://github.com/craftacademy/coding-as-a-craft-2-0/tree/7a0c900a8da40e73966aea1d8ad94fe9db55bceb/extras/naming_standards.md) section. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://craftacademy.gitbook.io/coding-as-a-craft-2-0/week-1-programming-basics-rubyt/the-atm-challenge.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.