I'm testing the return value of a function. Which of the two is the preferred way? test "extra verbose, using assert" do {:error, reason} = MyModule.my_fun assert reason == :nope end test "usin...

For debugging purposes during a failing integration test, I would like to still be able to see my application logs. Is there a command I can pass to the mix test task to accomplish this?

I'm trying to launch IEx.pry within a test. However I cannot get to run the tests within an iex session. Note that I'm not using mix. ExUnit.start defmodule Calc do def add(a,b) do a + b end e...

In Ruby, specifically RSpec, you can tell the test runner to abort on the first test that does not pass by the command-line flag --fail-fast. This helps a lot to not waste time or lose focus when f...

I am doing a channel test that is receiving lots of messages. I may receive a message during setup, adjust some state and then I want to assert ( or refute ) another copy of that message was sent. ...

Problem I want to test an Elixir module that interacts with the host system and has methods that have side effects. For this question and to keep it brief, assume it is the creation of several dir...

I have an authentication plug and I want to test my controllers. The problem is that the line in this plug has user_id = get_session(conn, :user_id) And it's always nil when I'm using this meth...

I have an Elixir program I'd like to test which gets input from the user via IO.gets several times. How would I go about faking this input in a test? Note: I would like to return a different valu...

We are trying to run each test in a completely clean dets environment, and each test is responsible for its own setup. We're running into issues where we can not completely remove the directory bet...

Is there a command-line invocation I can used in conjunction with mix that will output all test names without running the tests?

I wrote this test case: assert_raise ArgumentError, myFn(a,b) but it does not evaluate in the way I'd expect. myFn raises an ArgumentError (do: raise ArgumentError), but it is not caught by asse...

I have a method in my elixir app, let's say Some.Module.func/1, that returns a tuple of two numbers. I'm writing tests in ExUnit and only need to test the first element in tuple and don't really ca...