unit tests and fixes

src/providers/s3/s3_provider.cpp

@@ -362,6 +362,15 @@ auto s3_provider::get_directory_items(const std::string &api_path,
                                       directory_item_list &list) const
     -> api_error {
   try {
+    bool exists{};
+    auto res = is_directory(api_path, exists);
+    if (res != api_error::success) {
+      return res;
+    }
+    if (not exists) {
+      return api_error::directory_not_found;
+    }
+
     const auto cfg = get_config().get_s3_config();
     const auto is_encrypted = not cfg.encryption_token.empty();
     std::string key;