Lint Main File

.credo.exs

@@ -28,9 +28,7 @@
         excluded: [
           ~r"/_build/",
           ~r"/deps/",
-          ~r"/lib/diff_check.ex",
-          ~r"/test/support",
-          ~r"/test/diff_check_test.exs"
+          ~r"/test/support"
         ]
       },
       #

lib/diff_check.ex

@@ -1,14 +1,28 @@
 defmodule DiffCheck do
+  @moduledoc """
+  DiffCheck is a command-line tool that compares two files and prints the
+  differences between them.
+
+  The way this works is that it builds a 2D matrix of the two files by
+  computing for the longest subsequence between each files. It then prints
+  the differences between the two files by backtracking through the matrix.
+
+  The LCS implementation used is based on this Wikipedia article:
+
+  https://en.wikipedia.org/wiki/Longest_common_subsequence
+  """
+
   alias DiffCheck.BuildMatrix
   alias DiffCheck.PrintDiff
 
+  @spec main(args :: [String.t()], disable_printing :: boolean) :: :ok | {:error, String.t()}
   def main(args, disable_printing \\ false) do
     case validate_args(args) do
       :ok ->
         [file1_path, file2_path] = args
 
-        file1 = File.read!(file1_path) |> String.split("\n")
-        file2 = File.read!(file2_path) |> String.split("\n")
+        file1 = stringify_file(file1_path)
+        file2 = stringify_file(file2_path)
 
         file1
         |> BuildMatrix.call(file2)
@@ -46,4 +60,10 @@ defmodule DiffCheck do
 
     :ok
   end
+
+  defp stringify_file(file_path) do
+    file_path
+    |> File.read!()
+    |> String.split("\n")
+  end
 end

test/diff_check_test.exs

@@ -1,6 +1,5 @@
 defmodule DiffCheckTest do
-  use ExUnit.Case
-  doctest DiffCheck
+  use ExUnit.Case, async: true
 
   test "works with valid arguments" do
     file1 = Path.expand("support/fixtures/test_response_1.json", __DIR__)