anjanalp / airport-challenge-2022

Airport Challenge

This is a program to control the flow of planes at an airport. The planes can land and take off provided that the weather is sunny. Occasionally it may be stormy, in which case no planes can land or take off. A test driven approach has been taken in the creation of a set of classes to satisfy all the below user stories - test coverage is 100%.

A random generator has been used to set the weather (it is normally sunny but on occasion it may be stormy), which has been implemented in the Weather class and injected into the Airport class as a dependency, thereby ensuring each class maintains a single responsibility. Additionally, should sometime in the future one wants to, for example, use a weather forecasting API instead, it would be simple to do so whilst adhering to the open/closed principle.

The tests have used a stub to override random weather to ensure consistent test behaviour. Unit tests include test doubles to effectively isolate the single class being tested and feature tests check correct integration behaviour between the classes.

The code defends against edge cases such as inconsistent states of the system ensuring that planes can only take off from airports they are in; planes that are already flying cannot takes off and/or be in an airport; planes that are landed cannot land again and must be in an airport, etc.

User stores

As an air traffic controller
So I can get passengers to a destination
I want to instruct a plane to land at an airport

As an air traffic controller
So I can get passengers on the way to their destination
I want to instruct a plane to take off from an airport and confirm that it is no longer in the airport

As an air traffic controller
To ensure safety
I want to prevent landing when the airport is full

As the system designer
So that the software can be used for many different airports
I would like a default airport capacity that can be overridden as appropriate

As an air traffic controller
To ensure safety
I want to prevent takeoff when weather is stormy

As an air traffic controller
To ensure safety
I want to prevent landing when weather is stormy

How to setup

Clone the repo to your local machine, change into the directory and install the needed gems:

$ bundle install

To run the test suite:

$ rspec

Technologies used

• Ruby
• RSpec
• SimpleCov

Code example

3.1.0 :001 > require './lib/airport'
 => true
3.1.0 :002 > airport = Airport.new(Weather.new)
 => #<Airport:0x000000010675df58 @capacity=20, @hangar=[], @weather=#<Weather:0x000000010675dfd0>>
3.1.0 :003 > plane = Plane.new
 => #<Plane:0x00000001066777b0>
3.1.0 :004 > airport.land(plane)
Cannot land plane: weather is stormy (RuntimeError)
3.1.0 :005 > airport.land(plane)
 => [#<Plane:0x00000001066777b0 @airport=#<Airport:0x000000010675df58 @capacity=20, @hangar=[...], @weather=#<Weather:0x000000010675dfd0>>>]
3.1.0 :006 > airport.land(plane)
Cannot land plane: plane has already landed (RuntimeError)
3.1.0 :007 > airport.take_off(plane)
 => #<Plane:0x00000001066777b0 @airport=nil>
3.1.0 :008 > airport.take_off(plane)
Plane cannot take off: plane is already flying (RuntimeError)
3.1.0 :009 > small_airport = Airport.new(Weather.new, 1)
 => #<Airport:0x000000010680d8e0 @capacity=1, @hangar=[], @weather=#<Weather:0x000000010680d958>>
3.1.0 :010 > small_airport.land(plane)
 => [#<Plane:0x00000001066777b0 @airport=#<Airport:0x000000010680d8e0 @capacity=1, @hangar=[...], @weather=#<Weather:0x000000010680d958>>>]
3.1.0 :011 > another_plane = Plane.new
 => #<Plane:0x00000001066dd380>
3.1.0 :012 > small_airport.land(another_plane)
Cannot land plane: airport is full (RuntimeError)
3.1.0 :013 > airport.take_off(plane)
Cannot take off plane: plane is at another airport (RuntimeError)                                             
3.1.0 :014 > plane.airport
 =>#<Airport:0x000000010680d8e0 @capacity=1, @hangar=[#<Plane:0x00000001066777b0 @airport=#<Airport:0x000000010680d8e0 ...>>], @weather=#<Weather:0x000000010680d958>>           
3.1.0 :015 > another_plane.airport
 => nil
3.1.0 :016 > airport.land(another_plane)
 => [#<Plane:0x00000001066dd380 @airport=#<Airport:0x000000010675df58 @capacity=20, @hangar=[...], @weather=#<Weather:0x000000010675dfd0>>>]
3.1.0 :017 > another_plane.airport
 =>
#<Airport:0x000000010675df58 @capacity=20,@hangar=[#<Plane:0x00000001066dd380 @airport=#<Airport:0x000000010675df58 ...>>], @weather=#<Weather:0x000000010675dfd0>>