You're going through a technical interview with us at Xero, how exciting!
The purpose of this exercise is to get you building something that solves a tricky problem, let you think through it and start on it on your own, and then come in and walk us through your solution.
One of the core daily interactions that users have with the Xero mobile application is bank reconciliation, where bank transactions are matched against the corresponding accounting records (Invoices, Bills, etc.)
If an exact match is found, then the system will automatically suggest a match. There can also be multiple accounting records which match to a single transaction, but if some combination of the records sum to be an exact match, then the user has to find and select them themselves. Surely there is a better way!
If you run the application in this project you will see a single activity which displays a list of accounting records and the total amount of a transaction at the top, there's not much else to it! And that's where you come in.
You have two pieces of functionality to add. And we don't want you spending too much time on it, so if you run out of time or get stuck then don't worry, we can talk through it together during the interview.
- Wire up the behaviour so that when an accounting record is selected, it is subtracted from the remaining total at the top.
- When a subset of the accounting records sum to be an exact match of the remaining total, then automatically select them.
As you go, mark down any questions or concerns which come up, we would love to hear them as you walk us through the code during the upcoming interview.
Unit tests can be extremely helpful, especially for something like goal #2. Search for 'ExampleUnitTest' in this project to see where to put them.