Why deployment process matters in Blockchain / Solidity - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to deploy a smart contract using a deployment function.

Blockchain / Solidity

contract = [1]('MyContract')

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

Atest

Bcompile

Cdeploy

Drun

Attempts:

3 left

💡 Hint

Common Mistakes

Using compile instead of deploy

Trying to run the contract directly

Confusing test with deploy

The deploy function is used to send the smart contract to the blockchain network.

2fill in blank

medium

Complete the code to wait for the deployment transaction to be confirmed.

Blockchain / Solidity

tx_receipt = tx.wait([1])

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

A1

B10

C5

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Waiting for 0 confirmations which means no confirmation

Waiting for too many confirmations unnecessarily

Waiting for 1 confirmation ensures the deployment is recorded on the blockchain.

3fill in blank

hard

Fix the error in the deployment code by choosing the correct network parameter.

Blockchain / Solidity

network = [1]  # Choose the correct network for deployment

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

A'devnet'

B'mainnet'

C'localhost'

D'testnet'

Attempts:

3 left

💡 Hint

Common Mistakes

Deploying to testnet when real deployment is needed

Using localhost which is only for local testing

Deploying to 'mainnet' means the contract is live on the real blockchain.

4fill in blank

hard

Fill both blanks to set the gas limit and gas price for deployment.

Blockchain / Solidity

tx = contract.deploy(gas=[1], gasPrice=[2])

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

A3000000

B1000000000

C500000

D2000000000

Attempts:

3 left

💡 Hint

Common Mistakes

Setting gas limit too low causing deployment failure

Using incorrect gas price units

Gas limit is set to 3,000,000 and gas price to 1,000,000,000 wei for deployment.

5fill in blank

hard

Fill all three blanks to create a deployment script that compiles, deploys, and waits for confirmation.

Blockchain / Solidity

compiled = compiler.compile('[1]')
contract = blockchain.deploy(compiled)
tx_receipt = contract.tx.wait([2])
print('Contract deployed at:', contract.[3])

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

AMyContract.sol

B1

Caddress

DMyContract.py

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong file extension for the contract source

Not waiting for any confirmation

Printing an incorrect property instead of address

The script compiles MyContract.sol, waits for 1 confirmation, and prints the contract's address.

Practice

1. Why is the deployment process important in blockchain development?

easy

A. It slows down the blockchain network intentionally.

B. It automatically fixes all bugs in the code.

C. It removes the need for testing the code.

D. It makes the blockchain code live and accessible to users.

Solution

1. Step 1: Understand deployment purpose

   Deployment is the step where blockchain code is made live for users to interact with.

2. Step 2: Evaluate options

   Only It makes the blockchain code live and accessible to users. correctly states that deployment makes the code live and accessible. Other options are incorrect or misleading.

3. Final Answer:

   It makes the blockchain code live and accessible to users. -> Option D

4. Quick Check:

   Deployment = Making code live [OK]

Hint: Deployment means making your code live for users [OK]

Common Mistakes:

• Thinking deployment fixes bugs automatically
• Skipping testing because of deployment
• Believing deployment slows the network

2. Which of the following is the correct syntax to deploy a smart contract using a blockchain framework?

easy

A. deploy contract();

B. contract.deploy();

C. contract->deploy();

D. deploy.contract();

Solution

1. Step 1: Identify correct method call syntax

   In most blockchain frameworks, deploying a contract is done by calling a deploy method on the contract object, like contract.deploy();

2. Step 2: Check syntax correctness

   contract.deploy(); uses correct dot notation and method call syntax. Other options use invalid syntax or wrong order.

3. Final Answer:

   contract.deploy(); -> Option B

4. Quick Check:

   Method call syntax = contract.deploy(); [OK]

Hint: Use dot notation and parentheses for method calls [OK]

Common Mistakes:

• Using arrow (->) instead of dot (.)
• Placing 'deploy' before 'contract'
• Using dot after 'deploy' instead of before

3. Consider this simplified deployment code snippet:

let deployed = await contract.deploy();
console.log(deployed.address);

What will be the output if deployment is successful?

medium

A. Undefined, because deploy() returns nothing

B. An error message about missing address

C. The blockchain address where the contract is deployed

D. The source code of the contract

Solution

1. Step 1: Understand deploy() return value

   The deploy() method returns an object representing the deployed contract, which includes its blockchain address.

2. Step 2: Analyze console.log output

   console.log(deployed.address) prints the address where the contract is deployed, confirming success.

3. Final Answer:

   The blockchain address where the contract is deployed -> Option C

4. Quick Check:

   deploy() returns address object [OK]

Hint: deploy() returns deployed contract with address property [OK]

Common Mistakes:

• Assuming deploy() returns nothing
• Expecting source code as output
• Confusing address with error message

4. You wrote this deployment code but get an error:

let deployed = contract.deploy;
console.log(deployed.address);

What is the main problem?

medium

A. Missing parentheses to call deploy function

B. deploy is not a valid property of contract

C. console.log cannot print addresses

D. Variable 'deployed' is declared incorrectly

Solution

1. Step 1: Identify function call mistake

   contract.deploy is a function reference, but missing parentheses means it is not called.

2. Step 2: Understand effect on deployed variable

   Without calling deploy(), deployed is a function, so deployed.address is undefined causing error.

3. Final Answer:

   Missing parentheses to call deploy function -> Option A

4. Quick Check:

   Function call needs () [OK]

Hint: Always use () to call functions [OK]

Common Mistakes:

• Forgetting parentheses on function calls
• Thinking deploy is a property, not a function
• Blaming console.log for errors

5. You want to ensure your blockchain app is safe and reliable after deployment. Which step is MOST important before deploying?

hard

A. Test the smart contract thoroughly on a test network

B. Change contract code after deployment without redeploying

C. Deploy directly to mainnet without review

D. Skip testing to deploy faster

Solution

1. Step 1: Understand deployment risks

   Deploying untested code can cause bugs, security issues, or loss of funds.

2. Step 2: Identify best practice

   Testing on a test network before main deployment helps catch errors and ensures safety.

3. Final Answer:

   Test the smart contract thoroughly on a test network -> Option A

4. Quick Check:

   Testing before deployment = safety [OK]

Hint: Always test on testnet before mainnet deployment [OK]

Common Mistakes:

• Skipping testing to save time
• Deploying without code review
• Trying to change code after deployment without redeploy