Contract Lifecycle: Design, Development, and Deployment BDC Practice Questions (Page 2)

Questions 6–10

1. 6foundation · easy

   Why is it important to verify a smart contract's source code on a block explorer like Etherscan?

   • ATo increase the gas efficiency of the contract.
   • BTo make the contract upgradeable.
   • CTo automatically fix any bugs in the deployed contract.
   • DTo allow users to inspect the code and confirm it matches the deployed bytecode.
   Reveal Solution Discussion Select an answer first
2. 7expert · hard

   A developer is writing tests for a contract that has a `withdraw()` function. The function should revert if the caller has no balance. The developer writes the test using `expect(await contract.withdraw()).to.be.reverted;` but the test fails because the function does not revert. What is the most likely cause?

   • AThe test is calling the function as a view, not as a transaction.
   • BThe test is missing the `await` on the `expect` call.
   • CThe contract's `withdraw` function is not payable.
   • DThe test is using the default signer, which has a balance in the contract.
   Reveal Solution Discussion Select an answer first
4. 8foundation · easy

   Which network is specifically designed for testing smart contracts without using real funds?

   • AEthereum mainnet
   • BPrivate blockchain
   • CRinkeby testnet
   • DLocal development network
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5. 9expert · hard

   A team is designing a smart contract that will handle high-volume microtransactions. They need to minimize gas costs for users while maintaining security. They are considering using a proxy for upgradeability. What is the most important trade-off to evaluate?

   • AProxy contracts cannot be verified on block explorers
   • BProxy delegatecall adds a small gas overhead per transaction but enables future logic upgrades without changing the contract address
   • CProxy contracts require users to pay higher gas for every read call
   • DProxy contracts are inherently less secure than non-upgradeable contracts
   Reveal Solution Discussion Select an answer first
6. 10foundation · easy

   What is the purpose of a modifier in Solidity?

   • ATo specify the visibility of a function (public, private, etc.).
   • BTo define a new data type that can be used in multiple contracts.
   • CTo change the behavior of a function by adding reusable checks or logic.
   • DTo handle exceptions and errors that occur during function execution.
   Reveal Solution Discussion Select an answer first