shhavel / fuel_calculator_ruby

NASA Fuel Calculator: Application and CLI to calculate the fuel required for the flight.

FuelCalculator

NASA Fuel Calculator: Application and CLI to calculate the fuel required for the flight.

Installation

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec or bundle exec rspec to run the tests.

Interactive prompt

Run bin/console for an interactive prompt that will allow you to experiment:

irb(main):001> FuelCalculator.call(28801, [[:launch, "earth"], [:land, "moon"], [:launch, "moon"], [:land, "earth"]])
=> 51898
irb(main):002> FuelCalculator.call(28801, [[:launch, "earth"], [:launch, "moon"], [:land, "earth"]])
# raises Invalid path (FuelCalculator::ValidationError)

Mission Path Requirements

The mission should start with launching and end with landing, — we should not leave the ship without fuel in the space. The path must be consistent: the launch of a ship from a planet must be immediately preceded by a landing on the same planet, for all planets on the path except the first. Any ship landing on a planet must be immediately preceded by a launch from any planet, which may or may not be another planet.

CLI Installation

To install this gem onto your local machine, run bundle exec rake install and reopen the shell.

CLI Usage

The CLI interface is simplified. The user specifies a mass of the ship (including equipment) and a list of planets, and the program plans an appropriate launch/land path for the mission and calculates the amount of fuel.

$ fuel_calculator 28801 earth moon earth
51898

Install BATS for CLI testing

https://bats-core.readthedocs.io/en/stable/installation.html

Run BATS tests

$ bats test

Uninstall CLI

$ gem uninstall fuel_calculator