Parse working_dir switch

lib/cli.ex

@@ -4,11 +4,15 @@ defmodule Onigumo.CLI do
   }
 
   def main(argv) do
-    case OptionParser.parse(argv, strict: []) do
-      {[], [component], []} ->
+    case OptionParser.parse(
+           argv,
+           aliases: [C: :working_dir],
+           strict: [working_dir: :string]
+         ) do
+      {parsed_switches, [component], []} ->
         {:ok, module} = Map.fetch(@components, String.to_atom(component))
-        root_path = File.cwd!()
-        module.main(root_path)
+        working_dir = Keyword.get(parsed_switches, :working_dir, File.cwd!())
+        module.main(working_dir)
 
       _ ->
         usage_message()
@@ -19,11 +23,14 @@ defmodule Onigumo.CLI do
     components = Enum.join(Map.keys(@components), ", ")
 
     IO.puts("""
-    Usage: onigumo [COMPONENT]
+    Usage: onigumo [OPTION]... [COMPONENT]
 
     Simple program that retrieves HTTP web content as structured data.
 
     COMPONENT\tOnigumo component to run, available: #{components}
+
+    OPTIONS:
+    -C, --working-dir <dir>\tChange working dir to <dir> before running
     """)
   end
 end

test/onigumo_cli_test.exs

@@ -8,6 +8,16 @@ defmodule OnigumoCLITest do
     "uploader"
   ]
 
+  @invalid_switches [
+    "--invalid",
+    "-c"
+  ]
+
+  @working_dir_switches [
+    "--working-dir",
+    "-C"
+  ]
+
   describe("Onigumo.CLI.main/1") do
     for argument <- @invalid_arguments do
       test("run CLI with invalid argument #{inspect(argument)}") do
@@ -23,18 +33,33 @@ defmodule OnigumoCLITest do
       assert usage_message_printed?(fn -> Onigumo.CLI.main(["Downloader", "Parser"]) end)
     end
 
-    test("run CLI with invalid switch") do
-      assert usage_message_printed?(fn -> Onigumo.CLI.main(["--invalid"]) end)
+    for switch <- @invalid_switches do
+      test("run CLI with invalid switch #{inspect(switch)}") do
+        assert usage_message_printed?(fn -> Onigumo.CLI.main([unquote(switch)]) end)
+      end
     end
 
     @tag :tmp_dir
     test("run CLI with 'downloader' argument passing cwd", %{tmp_dir: tmp_dir}) do
-      expect(OnigumoDownloaderMock, :main, fn root_path -> root_path end)
+      expect(OnigumoDownloaderMock, :main, fn working_dir -> working_dir end)
 
       File.cd(tmp_dir)
       assert Onigumo.CLI.main(["downloader"]) == tmp_dir
     end
 
+    for switch <- @working_dir_switches do
+      @tag :tmp_dir
+      test("run CLI 'downloader' with #{inspect(switch)} switch", %{tmp_dir: tmp_dir}) do
+        expect(OnigumoDownloaderMock, :main, fn working_dir -> working_dir end)
+
+        assert Onigumo.CLI.main(["downloader", unquote(switch), tmp_dir]) == tmp_dir
+      end
+
+      test("run CLI 'downloader' with #{inspect(switch)} without any value") do
+        assert usage_message_printed?(fn -> Onigumo.CLI.main(["downloader", unquote(switch)]) end)
+      end
+    end
+
     defp usage_message_printed?(function) do
       output = capture_io(function)
       String.starts_with?(output, "Usage: onigumo ")