AirplaneQueue, toy class
by Bill Arndt

command to run tests:
rspec spec

A software subsystem of an air-traffic control system is defined to manage a queue of aircraft (AC) in an airport. The aircraft queue is managed by a process which responds to three types of requests:

- system boot used to start the system.

- enqueue aircraft used to insert a new AC into the system.

- dequeue aircraft used to remove an AC from the system.


AC’s have the following properties:

AC type: Passenger or Cargo

AC size: Small or Large

The process which manages the queue of AC’s satisfies the following:

There is no limit on the number of AC’s it can manage (could be tens of thousands)

Dequeue aircraft requests result in selection of one AC for removal such that:

Passenger AC’s have removal precedence over Cargo AC’s

Large AC’s of a given type have removal precedence over Small AC’s of the same type.

Earlier enqueued AC’s of a given type and size have precedence over later enqueued AC’s of the same type and size.