refactor backend module architecture

tests/test_wallpaper_service.py

@@ -0,0 +1,42 @@
+import app.services.image as image_service
+from app.services.image import WallpaperHelper, configure_wallpaper_providers
+
+
+def test_wallpaper_service_uses_startup_providers(monkeypatch):
+    """壁纸服务通过组合根注入的 provider 访问业务 Chain。"""
+    provider_names = (
+        "_tmdb_wallpaper_provider",
+        "_tmdb_wallpaper_list_provider",
+        "_mediaserver_wallpaper_provider",
+        "_mediaserver_wallpaper_list_provider",
+    )
+    for provider_name in provider_names:
+        monkeypatch.setattr(
+            image_service,
+            provider_name,
+            getattr(image_service, provider_name),
+        )
+    cached_methods = (
+        WallpaperHelper.get_tmdb_wallpaper,
+        WallpaperHelper.get_tmdb_wallpapers,
+        WallpaperHelper.get_mediaserver_wallpaper,
+        WallpaperHelper.get_mediaserver_wallpapers,
+    )
+    for method in cached_methods:
+        method.cache_clear()
+    try:
+        configure_wallpaper_providers(
+            tmdb_wallpaper=lambda: "tmdb-one",
+            tmdb_wallpapers=lambda count: [f"tmdb-{count}"],
+            mediaserver_wallpaper=lambda: "server-one",
+            mediaserver_wallpapers=lambda count: [f"server-{count}"],
+        )
+        helper = WallpaperHelper()
+
+        assert helper.get_tmdb_wallpaper() == "tmdb-one"
+        assert helper.get_tmdb_wallpapers(3) == ["tmdb-3"]
+        assert helper.get_mediaserver_wallpaper() == "server-one"
+        assert helper.get_mediaserver_wallpapers(4) == ["server-4"]
+    finally:
+        for method in cached_methods:
+            method.cache_clear()