How to advance block number when I’m developing on RSK Regtest?

Question

I have a smart contract that checks if the actual block number is higher than a fixed one to execute certain functionality and I need to write a unit test to validate that behavior. I’m using RSK in Regtest mode to execute tests and I would need to increment the block number without actually waiting for time to pass.

The smart contract uses a block number, and I need to increment the block number without actually waiting for time to pass.

context('once deployed', function () {
   it('can only be released after cliff', async function () {
     // TODO here I need to increment time or block number
     await this.lockup.release();
   });
)};

How can I do this in a truffle (mocha) test like the one above?

Answer 1

Quick note, to stress this is not possible in "actual" RSK blockchains (Mainnet and Testnet), as it involves "fake" mining.

However, in Regtest, this is indeed possible:

(1)

Use the evm_mine JSON-RPC method to mine blocks.

function evmMine () {
    return new Promise((resolve, reject) => {
        web3.currentProvider.send({
            jsonrpc: "2.0",
            method: "evm_mine",
            id: new Date().getTime()
            }, (error, result) => {
                if (error) {
                    return reject(error);
                }
                return resolve(result);
            });
    });
};

await evmMine(); // Force a single block to be mined.

This is consistent with the approach used in Ethereum developer tools, e.g. Ganache.

(2)

Use the evm_increaseTime JSON-RPC method to increase time of the block:

function evmIncreaseTime(seconds) {
    return new Promise((resolve, reject) => {
        web3.currentProvider.send({
            method: "evm_increaseTime",
            params: [seconds],
            jsonrpc: "2.0",
            id: new Date().getTime()
          }, (error, result) => {
            if (error) {
                return reject(error);
            }
            return asyncMine().then( ()=> resolve(result));
          });
    }); 
}

await evmIncreaseTime(600); // Force block to be mined such that ~10 minutes has passed