Blockchain Development Frameworks (Truffle, Hardhat) BDC Practice Questions (Page 3)

Questions 11–15

1. 11foundation · easy

   Which of the following is a core feature of the Hardhat framework?

   • AA built-in wallet for managing private keys and signing transactions
   • BA proprietary database for storing contract state
   • CA graphical user interface for managing smart contract deployments
   • DA built-in local Ethereum network that supports deterministic deployments
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2. 12foundation · easy

   In a Truffle project, how can a frontend dApp access the deployed contract artifacts?

   • ABy using a special Truffle API endpoint
   • BBy importing the JSON files from the build/contracts directory
   • CBy reading the contract source code directly
   • DBy querying the blockchain for the contract's bytecode
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4. 13expert · hard

   A developer is writing tests for a contract that has a function that can only be called once. They want to test that the second call reverts. The test uses Hardhat. Which approach is most reliable?

   • AUse a snapshot of the blockchain state before the first call, then revert to the snapshot and call the function again.
   • BCall the function once, then call it again and assert that the second call reverts.
   • CUse a mainnet fork and impersonate a different account for the second call.
   • DMock the contract to allow multiple calls and test the logic separately.
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5. 14application · medium

   A developer has a Hardhat project and wants to interact with a deployed contract from a Node.js script. They want to use the Hardhat Runtime Environment to get the contract factory and deploy a new instance. Which approach is correct?

   • AUse hre.artifacts.require('MyContract') to get the contract factory.
   • BUse hre.ethers.getContractFactory('MyContract') and then deploy it with the factory.
   • CUse hre.web3.eth.Contract to get the contract factory.
   • DUse require('@truffle/contract') to load the contract abstraction.
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6. 15expert · medium

   A developer needs to deploy a contract to multiple networks (local, testnet, mainnet) using the same Hardhat script. The script should use different constructor arguments depending on the network. Which approach is most maintainable?

   • ACreate a separate script for each network and duplicate the deployment logic.
   • BHardcode the constructor arguments in the script and change them manually before each deployment.
   • CUse environment variables to set the constructor arguments and require the developer to change them before each deployment.
   • DIn the script, read the network name from `hre.network.name` and use a configuration object to map network names to constructor arguments.
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