Blockchain Development Frameworks (Truffle, Hardhat) BDC Practice Questions (Page 9)

Questions 41–45

1. 41application · medium

   A developer is writing tests for a contract that has a function that should only be callable by the owner. They want to test that a non-owner account cannot call the function. Which testing approach should they use in Hardhat?

   • AUse a fork of the mainnet and impersonate a non-owner account.
   • BUse a mock contract that overrides the owner check.
   • CUse the signers from the Hardhat Network and connect the non-owner signer to the contract, then assert that the call reverts.
   • DUse the owner account to call the function and expect it to revert.
   Reveal Solution Discussion Select an answer first
2. 42application · medium

   A team is using Hardhat and wants to deploy the same contract to both a local network and a public testnet. They need to ensure that the deployment script works for both without modification. What is the best way to manage the network configurations?

   • ADefine both networks in hardhat.config.js and use the --network flag to select the target when running the script.
   • BUse environment variables to switch networks within the deployment script, but keep the RPC URLs hardcoded in the script.
   • CUse Truffle's migrations and define both networks in truffle-config.js.
   • DCreate two separate deployment scripts, one for each network, and manually change the RPC URL in each.
   Reveal Solution Discussion Select an answer first
4. 43application · medium

   A team is using Truffle for a project and needs to deploy a contract to a private blockchain. They want to keep the private key out of the configuration file and use an environment variable. Which approach should they use?

   • AUse the HDWalletProvider with the mnemonic read from process.env.MNEMONIC in truffle-config.js.
   • BUse the built-in Truffle provider, which automatically reads the private key from the environment.
   • CUse a custom provider that reads the private key from a local file without any environment variable.
   • DHardcode the private key in truffle-config.js and use it directly in the provider.
   Reveal Solution Discussion Select an answer first
5. 44application · easy

   A developer is starting a new Truffle project and wants to organize contracts, migrations, and tests in the standard directory structure. Which set of commands and folders is correct?

   • ARun `truffle create project` and manually create `src/`, `deploy/`, and `spec/` folders.
   • BRun `truffle scaffold` and use the `solidity/`, `deployments/`, and `test/` folders.
   • CRun `truffle init` and use the `contracts/`, `migrations/`, and `test/` folders that are created.
   • DRun `truffle new` and use the `contracts/`, `scripts/`, and `tests/` folders.
   Reveal Solution Discussion Select an answer first
6. 45expert · hard

   A developer is using Hardhat and wants to use a custom task that requires access to the Hardhat Runtime Environment. They have written the task in a separate file. How should they load it so that the task is available when running npx hardhat?

   • AUse the --task flag when running npx hardhat to specify the task file.
   • BRequire the file in hardhat.config.js using require('./tasks/myTask.js').
   • CAdd the file to the plugins folder and Hardhat will automatically load it.
   • DPlace the file in the scripts folder and run it with node scripts/myTask.js.
   Reveal Solution Discussion Select an answer first