CI/CD for smart contracts in Blockchain / Solidity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a GitHub Actions workflow that triggers on push to the main branch.

Blockchain / Solidity

on: [1]
jobs:
  build:
    runs-on: ubuntu-latest

Drag options to blanks, or click blank then click option'

Apush

Bpull_request

Cschedule

Drelease

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'pull_request' instead of 'push' triggers workflow on PRs, not code pushes.

Using 'schedule' runs on a timer, not on code changes.

The workflow triggers on push events to start the CI/CD process.

2fill in blank

medium

Complete the code to install the Solidity compiler in the CI job.

Blockchain / Solidity

steps:
  - name: Install Solidity
    run: npm install -g [1]

Drag options to blanks, or click blank then click option'

Atruffle

Bsolc

Csolidity

Dganache

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'truffle' or 'ganache' which are frameworks or test environments, not the compiler.

Using 'solidity' which is not the npm package name.

solc is the Solidity compiler package installed globally via npm.

3fill in blank

hard

Fix the error in the deployment script command to deploy the smart contract using Hardhat.

Blockchain / Solidity

npx hardhat [1] --network rinkeby

Drag options to blanks, or click blank then click option'

Arun

Btest

Ccompile

Ddeploy

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'deploy' which is not a built-in Hardhat command.

Using 'compile' or 'test' which do not deploy contracts.

The correct Hardhat command to run a deployment script is run.

4fill in blank

hard

Fill both blanks to create a GitHub Actions step that runs tests and reports coverage.

Blockchain / Solidity

- name: Run tests and coverage
  run: npx hardhat [1] && npx [2]

Drag options to blanks, or click blank then click option'

Atest

Bsolidity-coverage

Ccompile

Dlint

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'compile' or 'lint' instead of 'test' for running tests.

Using 'hardhat' commands that do not generate coverage.

The step runs hardhat test to test contracts and solidity-coverage to report coverage.

5fill in blank

hard

Fill all three blanks to define environment variables for deployment in GitHub Actions.

Blockchain / Solidity

env:
  PRIVATE_KEY: ${{ secrets.[1] }}
  INFURA_API_KEY: ${{ secrets.[2] }}
  ETHERSCAN_API_KEY: ${{ secrets.[3] }}

Drag options to blanks, or click blank then click option'

ADEPLOYER_PRIVATE_KEY

BINFURA_KEY

CETHERSCAN_KEY

DAPI_SECRET

Attempts:

3 left

💡 Hint

Common Mistakes

Using generic or incorrect secret names like 'API_SECRET'.

Mixing up the keys for Infura and Etherscan.

These are common secret names for deployment keys and API keys stored in GitHub Secrets.

Practice

1. What is the main purpose of using CI/CD pipelines for smart contracts?

easy

A. To manually write smart contract code faster

B. To avoid writing tests for smart contracts

C. To store smart contracts on a local machine only

D. To automate compiling, testing, and deploying smart contracts

Solution

1. Step 1: Understand CI/CD role in smart contracts

   CI/CD pipelines automate repetitive tasks like compiling, testing, and deploying smart contracts to reduce errors and save time.

2. Step 2: Compare options with CI/CD purpose

   Only To automate compiling, testing, and deploying smart contracts describes automation of compile, test, and deploy steps, which is the core of CI/CD.

3. Final Answer:

   To automate compiling, testing, and deploying smart contracts -> Option D

4. Quick Check:

   CI/CD automates smart contract lifecycle steps = B [OK]

Hint: CI/CD means automate build, test, deploy steps [OK]

Common Mistakes:

• Thinking CI/CD is for manual coding
• Confusing storage with deployment
• Skipping testing in CI/CD

2. Which of the following is the correct syntax to trigger a GitHub Actions workflow on every push to the main branch for smart contract CI/CD?

easy

A. on: push:
branches: [main]

B. trigger: push main

C. on_push: main_branch

D. when: push to main

Solution

1. Step 1: Identify correct GitHub Actions event syntax

   The correct syntax uses 'on:' followed by the event type and branches list, like 'on: push:\n branches: [main]'.

2. Step 2: Compare options to GitHub Actions docs

   Only on: push: branches: [main] matches the official YAML syntax for triggering workflows on push to main branch.

3. Final Answer:

   on: push: branches: [main] -> Option A

4. Quick Check:

   GitHub Actions uses 'on: push' with branches list = A [OK]

Hint: GitHub Actions uses 'on:' with event and branches [OK]

Common Mistakes:

• Using incorrect keywords like 'trigger' or 'when'
• Wrong indentation or missing colon
• Confusing event names

3. Given this GitHub Actions step in a smart contract pipeline:

 - name: Compile Contract
   run: solc --bin MyContract.sol -o build/

What will this command do?

medium

A. Run tests on MyContract.sol

B. Deploy MyContract.sol to blockchain network

C. Compile MyContract.sol and output binary files to build/ directory

D. Delete build/ directory

Solution

1. Step 1: Understand solc compile command

   The command 'solc --bin MyContract.sol -o build/' compiles the Solidity file and outputs binary files to the specified build directory.

2. Step 2: Match command purpose to options

   Only Compile MyContract.sol and output binary files to build/ directory correctly describes compiling and outputting binaries, while others describe unrelated actions.

3. Final Answer:

   Compile MyContract.sol and output binary files to build/ directory -> Option C

4. Quick Check:

   solc --bin compiles and outputs binaries = C [OK]

Hint: solc --bin compiles Solidity to binary output [OK]

Common Mistakes:

• Confusing compile with deploy
• Assuming tests run automatically
• Thinking it deletes files

4. You have this GitHub Actions step to deploy a smart contract:

 - name: Deploy Contract
   run: truffle migrate --network mainnet

But the deployment fails with an error about missing network configuration. What is the likely cause?

medium

A. The 'truffle migrate' command is misspelled

B. The 'mainnet' network is not defined in truffle-config.js

C. The GitHub Actions runner lacks internet access

D. The smart contract code has syntax errors

Solution

1. Step 1: Analyze error about missing network configuration

   The error indicates the deployment tool cannot find the 'mainnet' network settings in the configuration file.

2. Step 2: Identify cause of missing network config

   If 'mainnet' is not defined in truffle-config.js, deployment fails. Syntax errors or internet issues cause different errors, and the command spelling is correct.

3. Final Answer:

   The 'mainnet' network is not defined in truffle-config.js -> Option B

4. Quick Check:

   Missing network config causes deployment failure = D [OK]

Hint: Check truffle-config.js for network definitions first [OK]

Common Mistakes:

• Blaming code syntax for network config errors
• Ignoring configuration files
• Assuming internet issues without checking config

5. You want to ensure your smart contract CI/CD pipeline only deploys contracts after all tests pass and on the 'release' branch. Which GitHub Actions workflow snippet correctly enforces this?

hard

A. on:
push:
branches: [release]
jobs:
build:
steps:
- run: npm test
deploy:
needs: build
if: success()
steps:
- run: truffle migrate --network mainnet

B. on:
push:
branches: [main]
jobs:
deploy:
steps:
- run: truffle migrate --network mainnet

C. on:
pull_request:
branches: [release]
jobs:
test:
steps:
- run: npm test
deploy:
steps:
- run: truffle migrate --network mainnet

D. on:
push:
branches: [release]
jobs:
deploy:
steps:
- run: truffle migrate --network mainnet

Solution

1. Step 1: Identify branch trigger and job dependencies

   The pipeline triggers on push to 'release' branch. It runs tests first in 'build' job, then deploys only if tests succeed using 'needs: build' and 'if: success()'.

2. Step 2: Compare options for correct workflow logic

   on: push: branches: [release] jobs: build: steps: - run: npm test deploy: needs: build if: success() steps: - run: truffle migrate --network mainnet correctly sequences test then deploy with condition and branch filter. Others miss test step, branch, or job dependency.

3. Final Answer:

   on: push: branches: [release] jobs: build: steps: - run: npm test deploy: needs: build if: success() steps: - run: truffle migrate --network mainnet -> Option A

4. Quick Check:

   Test before deploy on release branch = A [OK]

Hint: Use job dependencies and branch filters in workflow [OK]

Common Mistakes:

• Deploying without testing first
• Triggering on wrong branch
• Missing job dependencies or conditions