CI/CD for smart contracts in Blockchain / Solidity - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of a smart contract deployment script

What is the output of this deployment script snippet when deploying a smart contract using Hardhat?

Blockchain / Solidity

const hre = require('hardhat');
async function main() {
  const Contract = await hre.ethers.getContractFactory('MyContract');
  const contract = await Contract.deploy();
  await contract.deployed();
  console.log('Contract deployed to:', contract.address);
}
main().catch((error) => {
  console.error(error);
  process.exitCode = 1;
});

A SyntaxError: Unexpected token

B Error: ContractFactory not found

C Contract deployed to: 0x1234567890abcdef1234567890abcdef12345678

D Contract deployment failed due to gas limit

💡 Hint

The script logs the deployed contract address on success.

The script deploys the contract and logs its address. Option C shows the expected output format.

🔀 Workflow

intermediate

Correct CI/CD pipeline step order for smart contracts

Which option shows the correct order of steps in a CI/CD pipeline for smart contracts?

A 1,2,3,4

B 2,1,3,4

C 1,3,2,4

D 3,1,2,4

💡 Hint

Linting should happen before compilation.

Static analysis and linting catch issues early, then compile, test, and deploy.

❓ Troubleshoot

advanced

Troubleshooting deployment failure due to missing private key

A CI job fails deploying a smart contract with this error: "Error: No private key provided". Which option is the most likely cause?

A The environment variable for the deployer's private key is not set in the CI environment.

B The smart contract code has a syntax error.

C The testnet network is down.

D The gas price is set too low.

💡 Hint

Private keys are usually stored as environment variables in CI.

The error indicates the deployer key is missing, likely due to unset environment variables.

✅ Best Practice

advanced

Best practice for managing secrets in smart contract CI/CD

Which option is the best practice for handling private keys and secrets in a smart contract CI/CD pipeline?

A Commit private keys directly into the repository for easy access.

B Store private keys encrypted in the CI tool's secret manager and inject them at runtime.

C Send private keys via email to the deployment server before each run.

D Hardcode private keys in the deployment scripts.

💡 Hint

Secrets should never be stored in code or sent insecurely.

Using the CI secret manager keeps keys safe and accessible only during deployment.

🧠 Conceptual

expert

Impact of immutable smart contracts on CI/CD updates

Given that deployed smart contracts are immutable, what is the best approach to update contract logic in a CI/CD pipeline?

A Use the same contract address and overwrite the bytecode with the new logic.

B Modify the existing contract code on the blockchain directly via the CI pipeline.

C Pause the blockchain network, update the contract, then resume the network.

D Deploy a new version of the contract and update references in the application to point to the new address.

💡 Hint

Smart contracts cannot be changed once deployed.

Because contracts are immutable, updates require deploying new contracts and redirecting usage.