# Watching Tests

Out of the box, Elixir comes with a fantastic [unit testing
framework](http://elixir-lang.org/docs/stable/ex_unit/ExUnit.html).
ExUnit can be run against our current project by running the `mix test`
command. Unfortunately, this runs the test once and quits. It doesn't
watch our project and rerun our suite when it detects changes.

Thankfully, the `mix_test_watch` dependency does exactly that. We can
add it to our project, and run the `mix test.watch` command, and our
suite will rerun on every file change.

Now that our test suite is up and running, we'll remove the example test
Elixir provided for us.

mix.exs

@@ -27,6 +27,8 @@ defmodule AdventOfCode01.Mixfile do
   #
   # Type "mix help deps" for more examples and options
   defp deps do
-    []
+    [
+      {:mix_test_watch, "~> 0.2", only: :dev}
+    ]
   end
 end

test/advent_of_code_01_test.exs

@@ -1,8 +1,4 @@
 defmodule AdventOfCode01Test do
   use ExUnit.Case
   doctest AdventOfCode01
-
-  test "the truth" do
-    assert 1 + 1 == 2
-  end
 end