When running on dev it will provide a REST JSON interface at port 4000 with a single endpoint /findCheapestOffer.

Which will return a single offer with the lowest price if found, otherwise it will return null.

$ AIR_FRANCE_KEY=xxx BRITISH_AIRWAYS_KEY=xxx mix do deps.get, app.start

Parameters

• origin: IATA code for origin airport
• destination: IATA code for destination airport
• departureDate: Date of the departure in the format "YYYY-MM-DD"

Example request:

http://localhost:4000/findCheapestOffer?origin=BER&destination=LHR&departureDate=2021-12-12

Application supervisor is defined at lib/air_price.ex

Cowboy and Plug are used to serve http.

The module AirPrice.Providers at lib/air_price/providers.ex exposes find_cheapest/1, fetch/1 and fetch/2, the first returns the cheapeast offer if any and the second all of the offers matching the criteria.

Fetching from all SOAP providers is performed concurrently using supervised Tasks. If a request fails it will be logged, but it will not prevent getting results from other providers.

Each of AirPrice.Poviders.AirFrance and AirPrice.Providers.British use a macro module AirPrice.Providers.Soap that will define the common functions for consuming the SOAP API. A SOAP provider must implement request_body/1 and parse/1.

No tests have been written, but I generally write enough unit tests to have confidence to refactor and as many integration tests to a have a good degree of confidence.

To mock requests I tend to define a Mock Plug server and dependency inject the url, here's an exaple for some other code exercise.

https://github.com/maca/air-quality-exercise/blob/master/test/mock_server.exs

taken from here:

https://medium.com/flatiron-labs/rolling-your-own-mock-server-for-testing-in-elixir-2cdb5ccdd1a0