truffle + testrpc time manipulation

Question

I use truffle + testrpc for testing my contracts and I need to test some time-dependant code (I guess that situation is quite common). I set some objects, check some conditions, then I need to simulate time forwarding to check conditions again.

Testrpc has evm_increaseTime function implemented. Can I use it in truffle tests? If yes, is it limited to javascript-written tests only? So far I wrote only solidity-tests.

I can't figure out what is the best way to use that evm_increaseTime function and how, though I am sure lots of people already solved that problem.

max taldykin · Accepted Answer · 2017-09-30T09:20:50.560

16

You can use evm_increaseTime from truffle console to adjust timestamp of the next block. Here is an example (from this answer):

> web3.eth.getBlock(web3.eth.blockNumber).timestamp
1500300000
> web3.currentProvider.send({jsonrpc: "2.0", method: "evm_increaseTime", params: [12345], id: 0})
{ id: 0, jsonrpc: '2.0', result: 12345 }
> web3.currentProvider.send({jsonrpc: "2.0", method: "evm_mine", params: [], id: 0})
> web3.eth.getBlock(web3.eth.blockNumber).timestamp
1500312345

It is not possible to call this from Solidity tests. Common practice is to override now or block.timestamp and update it's value manually:

contract X {
  struct FakeBlock {
    uint timestamp;
  }

  FakeBlock block;

  uint now;

  function setBlockTime(uint val) {
    now = val;
    block.timestamp = val;
  }
}

Notice, that now is an alias to the block.timestamp but when overriding only one of them, another one is not updated.

edited Sep 30 '17 at 09:20

answered Jul 18 '17 at 13:10

max taldykin

2,966
19
27

Thanks, is it possible to run some Solidity tests, then call evm_increaseTime from truffle console and then run another Solidity test with that new time? – Oleg Kondrakhanov Jul 18 '17 at 13:51
Don't think there is an easy way to do this. Truffle uses testrpc's snapshots to clean state between test bundles, so any changes issued from console will be reverted. – max taldykin Jul 18 '17 at 13:56
@maxtaldykin your method does not work for me, see https://ethereum.stackexchange.com/questions/27447/evm-increasetime-does-not-increase-timestamp – nubela Sep 29 '17 at 14:43

score 8 · Answer 2 · answered Jan 19 '18 at 14:56

I use zeppelin-solidity function in truffle tests

const increaseTime = function(duration) {
  const id = Date.now()

  return new Promise((resolve, reject) => {
    web3.currentProvider.sendAsync({
      jsonrpc: '2.0',
      method: 'evm_increaseTime',
      params: [duration],
      id: id,
    }, err1 => {
      if (err1) return reject(err1)

      web3.currentProvider.sendAsync({
        jsonrpc: '2.0',
        method: 'evm_mine',
        id: id+1,
      }, (err2, res) => {
        return err2 ? reject(err2) : resolve(res)
      })
    })
  })
}

truffle + testrpc time manipulation

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