fugue

Extendable testing utilities for Plug

Installation

Fugue is available in Hex and can be installed as:

1. Add fugue your list of dependencies in mix.exs:

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

Usage

Fugue extends ExUnit.Case by adding macros for calling Plug applications in an extendable way.

defmodule Test.MyApp do
  use Fugue, plug: MyApp

  test "root response" do
    request()
  after conn ->
    conn
    |> assert_status(200)
  end

  test "users read response" do
    user_id = "123" # this could come from a seed function

    request do
      path "/users/#{user_id}"
    end
  after conn ->
    conn
    |> assert_body_contains(user_id)
  end
end

Notice the setup and assertions are separated by an after keyword. The idea is to decouple the test case setup/generation from the actual test case execution. This ends up being useful in many ways. We could:

• generate cases on a single machine and distribute the requests around a cluster
• create benchmarks that exclude the setup time and just test the request rate (maybe even skip assertions entirely)
• serialize the requests into a file and run at a later time, or in a different language or service
• chain multiple tests together to create flow tests
• insert your crazy idea here

Fugue exposes several overridable functions to support this behavior:

execute/3

execute is the lowest level hook. It receives the request struct and a function handle for assertions. The default behavior is to call the call/2 function followed by the assertions:

defmodule Test.MyApp do
  use Fugue

  defp execute(request, assertions, context) do
    request
    |> call(context)
    |> assertions.()
  end
end

call/2

call receives the request struct and executes the request. In the case standard Plug apps this would look something like:

defmodule Test.MyApp do
  use Fugue

  def call(request, _context) do
    MyApp.call(request, [])
  end
end

When using Fugue, you may pass :plug and :plug_opts to the default call implementation:

defmodule Test.MyApp do
  use Fugue, plug: MyApp,
             plug_opts: []
end

init_request/1

init_request is passed the test context and can create the request struct. This is helpful for when something other than Plug.Conn is used or the default values for Plug.Conn need to be changed.

prepare_request/2

prepare_request is called just before calling execute/3 which allows for any final modifications to the request to be made.