Testing, Debugging, and Auditing Contracts BDC Practice Questions (Page 9)

Questions 41–45

1. 41expert · hard

   A development team is building a complex DeFi protocol with multiple interacting contracts. They have a tight deadline and need to decide how to allocate testing efforts. The team has limited resources and cannot write exhaustive tests for every function. Which testing strategy is most effective?

   • AWrite unit tests for every function first, then write integration tests if time permits.
   • BDeploy the contracts to a test network and perform manual testing without writing automated tests.
   • CRely solely on automated static analysis tools to identify vulnerabilities, and skip manual testing.
   • DPrioritize integration tests that cover the most critical user flows and interactions between contracts, and supplement with unit tests for the highest-risk functions.
   Reveal Solution Discussion Select an answer first
2. 42foundation · easy

   What is the recommended remediation for a reentrancy vulnerability?

   • ARemove all external calls from the contract.
   • BUse the checks-effects-interactions pattern and update state before making external calls.
   • CUse a different compiler version.
   • DIncrease the gas limit for the function.
   Reveal Solution Discussion Select an answer first
4. 43foundation · easy

   In a Solidity unit test using the Truffle framework, what is the purpose of the `assert` statement?

   • ATo log the transaction hash for debugging.
   • BTo verify that a function returns the expected value or that a state change occurred as expected.
   • CTo increase the gas limit for the test transaction.
   • DTo deploy the contract to the mainnet.
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5. 44foundation · easy

   What is the primary goal of integration testing in smart contract development?

   • ATo verify that multiple contracts work together correctly and interact with external dependencies as expected.
   • BTo measure the gas consumption of each function.
   • CTo test individual functions in isolation without any dependencies.
   • DTo deploy the contracts to a public testnet.
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6. 45application · medium

   A smart contract has a function that allows any user to set the contract's owner to themselves. The audit report lists this as a critical access control vulnerability. What is the best remediation?

   • AMake the function `internal` so only the contract itself can call it.
   • BRemove the function entirely and rely on the initial owner set in the constructor.
   • CAdd a modifier that restricts the function to the current owner and ensure the owner is set during deployment.
   • DAdd a require statement that checks `msg.sender == address(this)`.
   Reveal Solution Discussion Select an answer first