remix-project/libs/remix-lib/test/init.ts

const init = {
 overrideWeb3: function (web3, web3Override) {
  web3.eth.getCode = web3Override.getCode
  web3.debug.traceTransaction = web3Override.traceTransaction
  web3.debug.storageRangeAt = web3Override.storageRangeAt
  web3.eth.getTransaction = web3Override.getTransaction
  web3.eth.getTransactionFromBlock = web3Override.getTransactionFromBlock
  web3.eth.getBlockNumber = web3Override.getBlockNumber
 },

 readFile: function (filename, callback) {
  const fs = require('fs')
  try {
   console.log('reading ' + filename)
   if (callback) {
    fs.readFile(filename, 'utf8', callback)
   } else {
    return fs.readFileSync(filename, 'utf8')
   }
  } catch (e) {
   console.log(e)
   if (callback) {
    callback(e)
   } else {
    return e
   }
  }
 }
}

module.exports = init