         dbQueue.add(transactionObserver: observer)
         
         try dbQueue.inDatabase { db in
-            let artist = Artist(name: "Gerhard Richter")
+            let artist = Artist(id: nil, name: "Gerhard Richter")
             
             //
             try artist.save(db)

        do {
            try dbQueue.inTransaction { db in
                do {
                    try Artist(name: "Gerhard Richter").save(db)
                } catch {
                    XCTFail("Unexpected Error")
                }

        dbQueue.add(transactionObserver: observer)
        
        try dbQueue.inDatabase { db in
            let artist = Artist(id: nil, name: "Gerhard Richter")
            try artist.save(db)
            
            //
