It seems to be recommended to use block.number over block.timestamp for time-based operations (see Block Timestamp Manipulation: Preventative Techniques)

OpenZeppelin provides some APIs to simulate passing time. However, time.advaneBlockTo(target) is extremely slow, so unit testing a contract that uses block.number to simulate any large amount of time (say, 1 month) with this API will be prohibitively slow for the purpose of unit tests.

Are there any faster alternatives to simulate increasing block.number as a means of simulating the passage of time?

1 Answer 1


You can use:

  • Hardhat's evm_mine where your test.js file would look like this:

     const hre = require("hardhat") 
     //Do operation on block #N
     await hre.network.provider.send("evm_mine");
     //Do operation on block #N+1
  • Use OpenZeppelin's test helper advanceBlock where your test.js file would look like this:

     const { time } = 
     //Do something on block #N
     await time.advanceBlock();
     //Do something on block #N+1
  • Hi, Thanks for your response. Yes, you can use those APIs, however the issue is that they are very slow. For example, if a contract assumes average block time is 3s and wants to check if 30 days have passed, then it needs to check block #N+864000 (30 days * 24 hours * 60 minutes * 60 seconds / 3 seconds-per-block). Looping 864,000 and calling advanceBlock or evm_mine is not feasible for a unit test, so I am looking for alternatives.
    – EEE
    Dec 2, 2021 at 17:33

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