Testing with ethers.js in Blockchain / Solidity - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import ethers from the hardhat package.

Blockchain / Solidity

const { [1] } = require('hardhat');

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Acontract

Bweb3

Cethers

Dprovider

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'web3' instead of 'ethers' in Hardhat tests.

We import ethers from the hardhat package to interact with Ethereum in tests.

2fill in blank

medium

Complete the code to deploy a contract named 'SimpleStorage'.

Blockchain / Solidity

const SimpleStorage = await ethers.getContractFactory([1]);
const simpleStorage = await SimpleStorage.deploy();

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A'SimpleStorage'

B'Simple'

C'Storage'

D'StorageSimple'

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect or partial contract names.

The contract factory is created by passing the exact contract name as a string, here 'SimpleStorage'.

3fill in blank

hard

Fix the error in the test assertion to check if the stored value equals 42.

Blockchain / Solidity

expect(await simpleStorage.retrieve()).to.[1](42);

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AtoBe

Bequals

Ceq

Dequal

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'equals' or 'toBe' which are not valid Chai methods.

The correct Chai assertion method is equal to compare values.

4fill in blank

hard

Fill both blanks to wait for the deployment transaction to be mined.

Blockchain / Solidity

const tx = await simpleStorage.[1]();
await tx.[2]();

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Astore

Bwait

Cdeploy

Dsend

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'deploy' or 'send' instead of 'store' for the function call.

We call the store function to send a transaction, then wait to wait for it to be mined.

5fill in blank

hard

Fill all three blanks to write a test that checks if the stored value updates correctly.

Blockchain / Solidity

it('updates stored value', async function() {
  const tx = await simpleStorage.[1](100);
  await tx.[2]();
  const result = await simpleStorage.[3]();
  expect(result).to.equal(100);
});

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

Astore

Bwait

Cretrieve

Dupdate

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'update' instead of 'store' or 'retrieve'.

The test calls store to update, waits for mining with wait, then retrieves the value with retrieve to check it.