Using Pry to Help Test Phoenix Apps

In Rails, one thing that I love doing is to throw a pry in a test to make sure that my test environment is set up the correct way and to help debug while writing the code to get my tests to pass. The great thing about Phoenix is that you can similarly set up pry to do the same thing. Below, I will describe how I use pry when I test a Phoenix app.

First, for the file that you want to throw your IEx.pry into, add require IEx under your defmodule line.

defmodule Fishbowl.User do
  require IEx
  ...
end

Then, where you want to stop, enter IEx.pry

def changeset(model, params \\ :empty) do
  IEx.pry
  model
  ...

Run your test suite by running $ iex -S mix test --trace in your project directory.

iex -S will open up Elixir’s interactive shell so that your tests will stop when it hits an IEx.pry.

--trace will prevent your Elixir interactive shell from timing out after 60 seconds.

Happy testing!