```
make lint
networkdb/networkdb_test.go:88:2: should replace t.Error(fmt.Sprintf(...)) with t.Errorf(...)
networkdb/networkdb_test.go:136:2: should replace t.Error(fmt.Sprintf(...)) with t.Errorf(...)
make: *** [lint] Error 1
```
Signed-off-by: Lei Gong <lgong@alauda.io>