Behaviors

Interfacing to external dependencies with behaviors

The interface that the SoggyWaffle.WeatherAPI module provides is simple, as it’s made of just one function. However, if we expand the functionalities of the SoggyWaffle.WeatherAPI module, it would be hard to keep SoggyWaffle.FakeWeatherAPI up to date to mirror SoggyWaffle.WeatherAPI. This situation is a great use case for behaviors, in which Elixir modules define a set of functions (an interface) that other modules can agree to implement.

We can define a behavior that specifies how we want to interface with the weather API and then implement that behavior both in the real weather API interface and the fake one.