Improve test coverage.

app/Repositories/PiggyBank/PiggyBankRepositoryInterface.php

@@ -199,13 +199,6 @@ interface PiggyBankRepositoryInterface
      */
     public function getSuggestedMonthlyAmount(PiggyBank $piggyBank): string;
 
-    /**
-     * @param PiggyBankEvent $event
-     *
-     * @return int|null
-     */
-    public function getTransactionWithEvent(PiggyBankEvent $event): ?int;
-
     /**
      * Get for piggy account what is left to put in piggies.
      *