Strings Engineering

Backend Coding Exercise

Overview

This exercise serves as a demonstration of how you solve problems using idiomatic Go. Your solution will be used to facilitate a conversation during technical interviews.

Rules

There are a few guidelines to follow while completing this exercise:

Keep It Confidential: Please keep this document, the problem, and your solution confidential between yourself and Recursive Rebels (d.b.a. Strings), even after leaving the interview
24-hour Time Limit: This should be a relatively short but fun exercise to show of your knowledge about specific technologies and software engineering principles. Unless otherwise arranged, make handoff to Strings within 24 hours,
Use Generally Available Tools: The team evaluates new releases of tools and technologies as they become available, however for this exercise, please only use the latest version of tools and technologies that are considered Generally Available,
Open Documentation, Open Internet: Engineers spend a non-trivial amount of time sourcing information online; feel free to use online resources and be able to demonstrate why you selected one approach to solving a problem over another,
Deliver a Complete Project: The solution is delivered via a pull request. Fork the repository into your own, create the code, test cases, and any supporting documentation required to build the project should be standardized in your project resources -- We want to be able to run your solution on our machines.

Technical Requirements

All software projects require careful balance of both technical requirements along with functional requirements. Your solution must comply with the following technical objectives:

Implement your solution using a current released version of Go,
Do not use 3rd party libraries. Use only the core, standard library.
Must include unit tests to verify your components and include these tests in your solution,
Must not include a graphical user interface of any kind, or any API. Functions only.
There is no need to provide any form of data persistence.

We are looking for a clean, well-factored, idiomatic codebase that has accompanying unit tests.

Functional Requirements

Part 1

We would like a function that translates integers into strings that are English numerals.
For example, you can envision a function accepting an int and returning a string such that:

Input	Output
0	Zero
10	Ten
11	Eleven
55	Fifty-five
123	One hundred and twenty-three
1234	One thousand two hundred and thirty-four
85000	Eighty-five thousand

The following are the guard rails:

Minimum number is 0
Maximum number is 999,999,999
If a number group is in the range 21 to 99, and the second digit is not zero, the number is typically written as two words separated by a hyphen.

Part 2

Let's extend on our previous solution with something fun! In addition to supporting english, it's easy to envision that we could support other languages. Extend your solution such that we can also provide a selector to choose the language, and as an alternative, use Roman Numerals.