This is a rails 4.2.7.1 application that simulates a game of roulette.
- Players start with $10,000 when created.
- They will bet between 8 and 15 percent of their money each hand if it isn't raining in Santiago in the next 7 days.
- They will bet between 4 and 10 percent if it is going to rain.
- They will guess green 2% of the time, red 49% of the time, and black 49% of the time.
- The Roulette game determines the color using the same percentages for odds.
- Black/red double the wager.
- Green gives x15 the wager.
- At midnight players get $10,000 added to their purse.
Clone the repo: git clone git@github.com:gnfisher/roulette_on_rails.git
cd into the directory: cd roulette_on_rails
Run the setup script: bin/setup
Start foreman: foreman start
Open http://localhost:3000 in your browser.
Note that it takes three-minutes for the first game to run. Another game runs automatically every three-minutes afterwards thereon.
This project uses:
- RSpec and Capybara for testing
- DelayedJob for background jobs
- DelayedJob Recurring for scheduling recurring tasks
- OpenWeather gem for fetching the weather for the next 7 days.
- Kaminari for paginating
In this project a few basic techniques are employed:
- WeatherChecker wraps the OpenWeather API, a pretty basic example of the Adapter pattern.
- WagersSortedByRoundQuery is an extracted query object. It's pretty basic, too.
- WagerCalculator was the result of another refactoring (extract class).
- RouletteGame is the main entry point to the Roulette game. Its a task that includes DelayedJob Recurring and runs every three minutes. It fetches the current active players (with money) and passes them to RouletteRound.
- RouletteRound is the heart of the app. It fetches the weather report, generates a result for the roulette wheel for the round, and then passes each player to the PlayerRoundJob with the necessary information to complete there round for each player.
- PlayerRound collaborates with WagerCalculator to determine how much a player will bet and with RouletteGame to pick a color to wager on. It also collaborates with RouletteGame to determine the amount of winnings. Finally, it locks the player record and saves the new wager record with the data and also makes sure to update the Player record's money with any winnings/losses.
That's the core of it. There's also a NightlyDepositTask that runs a NighltyDepositJob, adding 10,000 to the balance of each player at 00:01am every day, as well as the ActiveRecord models for Wager, Player, etc.
I think the app does a decent job of using Object Oriented Design principles to keep things loosely coupled and easy to reason about.
The entire project was carried out using Discovery Testing techniques. Essentially, starting with a feature spec and working top down to discover value objects and collaborator objects, and then writing specs for those. I didn't write tests for the rake tasks nor for the WeatherChecker class. This was a code challenge and I had already put in the recommended time and so left those without an coverage.