Added test to verify delete raises on deleting undeletable facts
Added test to verify delete raises on deleting undeletable facts

Factlink/factlink-core,Factlink/factlink-core,daukantas/factlink-core,Factlink/factlink-core,Factlink/factlink-core,daukantas/factlink-core,daukantas/factlink-core,daukantas/factlink-core