How to simulate block minting in smart contracts unit test?

Question

I am writing a smart contract for staking. Earnings are increased each time a new block is minted. In order to test the calculation of earnings, I need to simulate a certain number of blocks to be minted in my test suite. Is there a function in web3.js to do this?

Answer 1

Web3js is "just" a wrapper for RPC method calls to the node, so the exact method depends on your node emulator.

However most emulators implement the evm_mine RPC method allowing you to mine an empty block within the emulator network.

web3.currentProvider.send({
    jsonrpc: "2.0",
    method: "evm_mine",
    id: 1
}, (error, response) => {
    console.log(response);
});

Docs:

• Ganache: https://docs.nethereum.com/en/latest/ethereum-and-clients/ganache-cli/
• Hardhat: https://hardhat.org/hardhat-network/docs/overview#mining-modes