Blockchain Development Frameworks (Truffle, Hardhat) BDC Practice Questions (Page 2)

Questions 6–10

1. 6expert · medium

   A developer is writing a Hardhat test for a contract that has a function which can only be called by the owner. The test needs to verify that a non-owner cannot call the function. Which approach is correct?

   • AUse `contract.connect(otherSigner).function()` and expect it to succeed.
   • BUse `contract.callFunction({ from: otherAddress })` to call the function from a different account.
   • CUse `this.contract.connect(otherSigner)` to call the function from a different account and expect it to revert.
   • DUse `contract.function(otherAddress)` and expect it to revert.
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2. 7application · medium

   A developer has deployed a contract using Hardhat and wants to interact with it from a React frontend. They have the contract address and ABI. Which approach is correct?

   • AUse the Hardhat runtime environment in the frontend to access the contract.
   • BUse Truffle's `truffle-contract` library in the frontend, even though the project uses Hardhat.
   • CImport the contract's Solidity source file directly into the React component and call functions.
   • DUse ethers.js in the frontend to create a contract instance with the address and ABI, then call its functions.
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4. 8application · medium

   A developer is debugging a smart contract that behaves unexpectedly during a test. They want to see the values of local variables and the call stack at a specific point in the contract execution. Which Hardhat feature should they use?

   • AUse the Hardhat Network's built-in stack traces, which are always enabled and show all local variables.
   • BAdd console.log statements in JavaScript and run the test with mocha.
   • CUse Hardhat's console.log in the contract and run the test with the Hardhat Network.
   • DUse Truffle's debugger by running truffle debug <transaction-hash>.
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5. 9foundation · easy

   Which command runs the automated tests in a Truffle project?

   • Atruffle check
   • Btruffle run test
   • Ctruffle test
   • Dtruffle verify
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6. 10expert · medium

   A developer wants to use a Hardhat plugin that adds a new task to the CLI. After installing the plugin and requiring it in `hardhat.config.js`, the task is not available when running `npx hardhat`. What is the most likely cause?

   • AThe plugin is not compatible with the installed Hardhat version.
   • BThe plugin requires a network to be configured before it can be used.
   • CThe plugin was installed as a dev dependency instead of a regular dependency.
   • DThe plugin was required in a file other than `hardhat.config.js`.
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