I run geth on testnet with --mine option. Seems mining is running. What log will be showed if mining success?
INFO [07-16|04:02:56] Starting mining operation
INFO [07-16|04:02:56] Commit new mining work number=1308362 txs=0 uncles=0 elapsed=260.17µs
INFO [07-16|04:02:57] Generating DAG in progress epoch=43 percentage=6 elapsed=11.383s
INFO [07-16|04:02:59] Generating DAG in progress epoch=43 percentage=7 elapsed=12.867s