func runCommands(t *testing.T, s common.Storage, cmds []interface{}) { for _, cmd := range cmds { var err error switch cmd := cmd.(type) { case common.GetMsg: err = s.Get(cmd.Id) case common.PutMsg: err = s.Put(cmd.Id) case common.DelMsg: err = s.Delete(cmd.Id) default: t.Fatal("unrecognized command") } if err != nil { t.Fatalf("command '%v' failed: %v", cmd, err) } } }