Verification progress tests #17352

While trying to test #17328, I noticed that:

1. We don't test the verification progress (verificationprogress field in getblockchaininfo)
2. The verification progress would always be 1 on regtest (even during IBD), both in the verificationprogress field of getblockchaininfo, or in the "new best" log message. (I tested this with 3 nodes, node 1 being the transaction spammer, node 2 the miner, node 3 the logger in both normal and blocksonly modes)

Is 2) due to some regtest special behavior I don't know about ? .1) is not that bad since it seems to work well in main and test networks, but might be a good first issue ?

I think I'm starting to understand why, historically, there are no tests for this. The "verification progress" was added as at most a heuristic, and the tests should not set one particular way of estimating progress in stone as it might be improved or changed.

A sanity check couldn't hurt, I guess.

It doesn't work for regtest because no statistics on transaction rate are known for regtest. It is not possible for the current approach to work on regtest.

Just to clarify: progress is computed as the ratio between the total number of processed transactions and an estimate of the total number of transactions in the chain. The latter relies on statistics.

Ok thank you for the clarification ! I think I can close this then.