Mock Onigumo.Downloader in CLI tests

Onigumo.Component is a behavior that can be mocked. CLI tests don’t
verify behavior of concrete components. Defined a mock for the
Downlaoader components so the CLI tests only verifies its call, not
its behavior.

Defined the expect mock to return the passed working directory to test
it’s set properly.

config/dev.exs

@@ -1,3 +1,4 @@
 import Config
 
 config(:onigumo, :http_client, HTTPoison)
+config(:onigumo, :downloader, Onigumo.Downloader)

config/test.exs

@@ -1,3 +1,4 @@
 import Config
 
 config(:onigumo, :http_client, HTTPoisonMock)
+config(:onigumo, :downloader, OnigumoDownloaderMock)

lib/cli.ex

@@ -1,6 +1,6 @@
 defmodule Onigumo.CLI do
   @components %{
-    :downloader => Onigumo.Downloader
+    :downloader => Application.compile_env(:onigumo, :downloader)
   }
 
   def main(argv) do

test/onigumo_cli_test.exs

@@ -18,13 +18,15 @@ defmodule OnigumoCLITest do
     test("run CLI with 'downloader' argument", %{tmp_dir: tmp_dir}) do
       expect(HTTPoisonMock, :start, fn -> nil end)
       expect(HTTPoisonMock, :get!, length(@urls), &HttpSupport.response/1)
+      expect(OnigumoDownloaderMock, :main, fn root_path -> root_path end)
 
       input_path_env = Application.get_env(:onigumo, :input_path)
       input_path_tmp = Path.join(tmp_dir, input_path_env)
       input_file_content = InputSupport.url_list(@urls)
       File.write!(input_path_tmp, input_file_content)
       File.cd(tmp_dir)
-      Onigumo.CLI.main(["downloader"])
+
+      assert Onigumo.CLI.main(["downloader"]) == tmp_dir
     end
 
     for argument <- @invalid_arguments do

test/test_helper.exs

@@ -1,3 +1,4 @@
 ExUnit.start()
 
 Mox.defmock(HTTPoisonMock, for: HTTPoison.Base)
+Mox.defmock(OnigumoDownloaderMock, for: Onigumo.Component)