Shaun Watson Backend Task

[ShaunWatson24]

Overview

This PR introduces a solution for the assigned Backend Task to retrieve the daily exchange rate data from the Czech National Bank for a collection of desired currencies and to display this information clearly in a simple console application.

Solution

My primary aim for this solution was to keep it simple and readable, following clean code principles and ensuring the solution would be easy to extend and maintain. I've included appropriate Error Handling and demonstrated the use of Structured Logging (I would probably reduce the quantity of logging in a real world scenario to avoid bloat and reduce costs). The solution consists of an ExchangeRateService (which simply calls the CNB api to get the daily exchange rates) which is injected into the ExchangeRateProvider class (which filters and returns the Exchange Rates). I did not adjust the provided skeleton too much as I felt this was not the focus of the task. Additionally, I added a Helper to calculate when the next exchange rates will be available from the CNB api. Finally, I added some formatting to the console output to make it more human readable in a graph format with appropriate columns (see screenshot).

All classes have appropriate unit tests in the ExchangeRateUpdater.Tests Project which ensure 100% code coverage, although given code coverage is not a reliable metric of test quality I have also added a settings file and instructions on how to run Stryker, which is a mutation testing tool to evaluate the quality of the tests.

Possible Future Improvements

• Implement Caching (e.g. using an InMemoryCache) if application was long running.
• Additional User Functionality (e.g. refreshing the result & outputting the difference to the previous days rates).
• Consider Czech Public Holidays when calculating the next available exchange rates.

Data Sources

Swagger API: https://api.cnb.cz/cnbapi/swagger-ui.html#/
Additional Context: https://www.cnb.cz/en/financial-markets/foreign-exchange-market/central-bank-exchange-rate-fixing/central-bank-exchange-rate-fixing/index.html

Additional Comments

• Atomic Commits I considered atomic commits only after my first commit, however each commit has an appropriate description which tells a story of how I tackled the task.
• Primary Constructors I have utilized Primary Constructors in this solution, although personally I'm not entirely sold on them yet as they make some classes slightly less readable.

Example Console Output