Fork testing (mainnet fork) in Blockchain / Solidity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Hardhat network helpers for mainnet forking.

Blockchain / Solidity

const { [1] } = require('hardhat');

Drag options to blanks, or click blank then click option'

Anetwork

Bethers

Cweb3

Dfs

Attempts:

3 left

💡 Hint

Common Mistakes

Importing 'ethers' instead of 'network'.

Using 'web3' which is not part of Hardhat by default.

We import network from Hardhat to configure mainnet forking.

2fill in blank

medium

Complete the code to set the mainnet fork URL in the Hardhat config.

Blockchain / Solidity

module.exports = {
  networks: {
    hardhat: {
      forking: {
        url: '[1]'
      }
    }
  }
};

Drag options to blanks, or click blank then click option'

A'https://mainnet.infura.io/v3/YOUR-PROJECT-ID'

B'http://localhost:8545'

C'https://kovan.infura.io/v3/YOUR-PROJECT-ID'

D'https://rinkeby.infura.io/v3/YOUR-PROJECT-ID'

Attempts:

3 left

💡 Hint

Common Mistakes

Using testnet URLs like Rinkeby or Kovan.

Using localhost URL which is not a mainnet fork.

The mainnet fork URL must point to the Ethereum mainnet RPC endpoint, such as Infura's mainnet URL.

3fill in blank

hard

Fix the error in the code to reset the Hardhat network fork block number.

Blockchain / Solidity

await network.provider.request({
  method: 'hardhat_reset',
  params: [{
    forking: {
      jsonRpcUrl: '[1]',
      blockNumber: 12345678
    }
  }]
});

Drag options to blanks, or click blank then click option'

A'https://rinkeby.infura.io/v3/YOUR-PROJECT-ID'

B'https://kovan.infura.io/v3/YOUR-PROJECT-ID'

C'https://mainnet.infura.io/v3/YOUR-PROJECT-ID'

D'http://localhost:8545'

Attempts:

3 left

💡 Hint

Common Mistakes

Using testnet URLs causes fork reset to fail.

Using localhost URL does not reset the mainnet fork.

The jsonRpcUrl must be the mainnet RPC URL to reset the fork correctly.

4fill in blank

hard

Fill both blanks to create a forked provider and get the block number.

Blockchain / Solidity

const provider = new ethers.providers.JsonRpcProvider([1]);
const blockNumber = await provider.getBlockNumber();
console.log('Forked block number:', [2]);

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A'http://localhost:8545'

BblockNumber

C'https://mainnet.infura.io/v3/YOUR-PROJECT-ID'

Dprovider

Attempts:

3 left

💡 Hint

Common Mistakes

Using mainnet URL instead of localhost URL.

Printing the provider object instead of the block number.

Use the Hardhat RPC URL to create the provider for the forked network and then print the block number variable.

5fill in blank

hard

Fill all three blanks to advance the forked network to a specific block and get its timestamp.

Blockchain / Solidity

await network.provider.request({
  method: '[1]',
  params: [{
    blockNumber: [2]
  }]
});
const block = await ethers.provider.getBlock([3]);
console.log('Block timestamp:', block.timestamp);

Drag options to blanks, or click blank then click option'

Ahardhat_mine

Bhardhat_reset

C12345678

Dhardhat_setBlockNumber

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong method names like 'hardhat_mine'.

Using different block numbers in method and getBlock call.

The method hardhat_setBlockNumber advances the fork to the given block number, which is then used to get the block timestamp.