go-ethereum: SimulateBackend AdjustTime is not adjusting time at all, or either in unexpected ways

Question

While using SimulateBackend I attempted to roll forward the time of the simulated blockchain using AdjustTime(604800 *time.Second) which should roll forward time by a week. Checking the returned error value shows that it is nil, however from all my testing it appears that time does not actually roll forward, and local system time is used. Attempting to call functions which should work after time is rolled forward, do not work.

go version: go1.10.11 linux/amd64

Using the lates go-ethereum version.

Answer 1

Are you doing a client.Commit() afterwards. I can't remember if it is necessary - but I have got into the habit of doing it so I assume it is.

The only way you will be able to test this function is to have a function that returns now or block.timestamp

I do this by having a small contract :

pragma solidity ^0.4.24;

contract Canary {

    function timeStamp() constant returns (uint256) {
        return now;
    }
}

This allows you to check the time before and after adjusting the time - or (for example) during a crowdsale - to adjust the time to a specific new time, e.g. sale start.

now, err := canary.TimeStamp(nil)
if err != nil {
    log.Fatal(err)
}

timeOffset := new(big.Int).Sub(targetTime, now).Int64()
c.AdjustTime(time.Duration(timeOffset) * time.Second)
c.Commit()

This only fails if you try to take the simulated chain ahead of your real current time.