A Bit of Testing Infrastructure

import { JsonRpcProvider } from '@ethersproject/providers';
import axios, { AxiosResponse } from 'axios';
import * as dotenv from 'dotenv';
import { Signer } from 'ethers';
 
dotenv.config();
 
// describes forking request. network_id is the only required attribute,
// but feel free to override any
type TenderlyFork = {
  block_number?: number;
  network_id: string;
  initial_balance?: number;
  chain_config?: {
    chain_id: number;
  };
};
 
// All you need to access the forked environment from your tests
export type EthersOnTenderlyFork = {
  provider: JsonRpcProvider;
  /** test accounts: map from address to given address' balance */
  accounts: { [key: string]: string };
  /** test accounts: signers for transactions*/
  signers: Signer[];
  /** a function to remove fork from Tenderly infrastructure, meant for test clean-up */
  removeFork: () => Promise<AxiosResponse<any, any>>;
};
 
const anAxiosOnTenderly = () =>
  axios.create({
    baseURL: 'https://api.tenderly.co/api/v1',
    headers: {
      'X-Access-Key': process.env.TENDERLY_ACCESS_KEY || '',
      'Content-Type': 'application/json',
    },
  });
/**
    Create a fork on Tenderly with parameters declared through the 
    fork parameter.
*/
export const forkForTest = async (fork: TenderlyFork): Promise<EthersOnTenderlyFork> => {
  const projectUrl = `account/${process.env.TENDERLY_ACCOUNT_SLUG}/project/${process.env.TENDERLY_PROJECT_SLUG}`;
  const axiosOnTenderly = anAxiosOnTenderly();
 
  const forkResponse = await axiosOnTenderly.post(`${projectUrl}/fork`, fork);
  const forkId = forkResponse.data.root_transaction.fork_id;
  console.info('Forked with fork id:', forkId);
  const provider = new JsonRpcProvider(`https://rpc.tenderly.co/fork/${forkId}`);
 
  const accounts = forkResponse.data.simulation_fork.accounts;
 
  const signers = Object.keys(accounts).map(address => provider.getSigner(address));
  console.log('Accounts on fork', accounts);
 
  return {
    provider,
    accounts,
    signers,
    removeFork: async () => {
      console.log('Removing test fork', forkId);
      return await axiosOnTenderly.delete(`${projectUrl}/fork/${forkId}`);
    },
  };
};