PncCodingExercise

This projects contains two existing modules that you will be asked to modify in order to satisfy a few requirements. You will also need to implement a few test cases.

RateLimiter is a GenServer that implements a Token Bucket rate limiter. It is a naive implementation and only works to rate limit requests at 5 per second.

ExternalService is a simple module that mimics an external network call with a response delay of 1s.

Requirements

• Write a test to make sure that our RateLimiter does in fact work as expected. (you can find the spec in test/rate_limiter_test.exs with some empty test cases ready)

• Update RateLimiter to call the ExternalService whenever RateLimiter.request/0 is called.

• Write a RateLimiter test that checks weather or not ExternalService receives the call. Note that we want to keep the 1s delay in ExternalService but also don't want to have our tests to hang (ie. if testing 5 requests, it's not acceptable that tests take 5s+ to run).

Stretch exercise

• Update RateLimiter and make it work with a configurable rate limiting. What are the settings we need to implement for that ?

Installation

If available in Hex, the package can be installed by adding pnc_coding_exercise to your list of dependencies in mix.exs:

def deps do
  [
    {:pnc_coding_exercise, "~> 0.1.0"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/pnc_coding_exercise.