hardening the check if a listing is active

lib/provider/sparkasse.js

@@ -36,7 +36,7 @@ const config = {
   },
   normalize: normalize,
   filter: applyBlacklist,
-  activeTester: checkIfListingIsActive,
+  activeTester: (url) => checkIfListingIsActive(url, 'Angebot nicht gefunden'),
 };
 export const init = (sourceConfig, blacklist) => {
   config.enabled = sourceConfig.enabled;