Add tests for Last.fm controller

test/music_library_web/controllers/last_fm_controller_test.exs

@@ -0,0 +1,46 @@
+defmodule MusicLibraryWeb.LastFmControllerTest do
+  use MusicLibraryWeb.ConnCase
+
+  describe "GET /auth/last_fm/callback" do
+    @tag :logged_out
+    test "on success, stores session key and redirects with flash", %{conn: conn} do
+      session_xml = """
+      <?xml version="1.0" encoding="UTF-8"?>
+      <lfm status="ok">
+        <session>
+          <name>testuser</name>
+          <key>test-session-key</key>
+          <subscriber>0</subscriber>
+        </session>
+      </lfm>
+      """
+
+      Req.Test.stub(LastFm.API, fn conn ->
+        Req.Test.text(conn, session_xml)
+      end)
+
+      conn = get(conn, ~p"/auth/last_fm/callback", %{"token" => "test-token"})
+
+      assert redirected_to(conn) == "/"
+      assert conn.assigns.flash["info"] =~ "Successfully connected"
+    end
+
+    @tag :logged_out
+    @tag :capture_log
+    test "on error, redirects with error flash", %{conn: conn} do
+      error_json = %{
+        "error" => 4,
+        "message" => "Invalid authentication token"
+      }
+
+      Req.Test.stub(LastFm.API, fn conn ->
+        Req.Test.json(conn, error_json)
+      end)
+
+      conn = get(conn, ~p"/auth/last_fm/callback", %{"token" => "bad-token"})
+
+      assert redirected_to(conn) == "/"
+      assert conn.assigns.flash["error"] =~ "Failed to connect"
+    end
+  end
+end