Solidity - lesson 4 | HackIndia Skills

Key point

One job

A test proves your contract keeps its promise after each change. For this track, your repo must show that the contract builds and the important actions are checked locally before testnet deployment.

Why Hardhat here

Hardhat 3 is a current mainstream Solidity toolkit. It supports Solidity tests, TypeScript tests, and fuzzing.

A default Hardhat 3 project gives you the folders recruiters expect to see: contracts, test, scripts, ignition/modules, and hardhat.config.ts.

Your to-do

Start the project

Do each one yourself, then tap it to tick it off. The ticks are only a checklist for you: they are not marked or scored.

Check that your machine has Node.js v22.13.0 or later.
Create or open your project folder.
Initialize Hardhat with npx, pnpm, or yarn.
Choose a basic project when prompted.
Commit the generated structure before adding your own contract.

0 of 5 done

npx hardhat --init

# or, if you use pnpm
pnpm dlx hardhat --init

# or, if you use yarn
yarn dlx hardhat --init

What to test

Do not test only that the contract deploys. Test the rules a user can break.

For a college project, cover the happy path, at least one rejected action, and one edge case. If your contract has an owner-only function, test that a non-owner cannot call it.

Example

Test plan example

Write the plan before asking AI to generate test code. This keeps the AI from testing random things that look correct but miss your actual rules.

Contract: EventPass

Rules to test:
1. The deployer becomes the organizer.
2. A student can register with a name and college.
3. The same wallet cannot register twice.
4. Only the organizer can close registrations.
5. Registration fails after registrations are closed.
6. The contract emits an event when a student registers.

Tip

Use AI carefully

You can ask ChatGPT, Gemini, or Claude to draft Hardhat tests from your contract. Paste the contract and your test plan, then ask for tests that match your project type.

Check the output. It should import from your actual files, use the function names in your contract, and assert failures for restricted actions. Delete tests for features your contract does not have.

Prompt:
I have this Solidity 0.8.x contract. Write Hardhat 3 tests for the rules below.
Use the existing folder structure: contracts/ and test/.
Do not invent functions.
Include tests for success cases and expected reverts.

Rules:
[paste your test plan]

Contract:
[paste your contract]

Common mistake

Common weak tests

Beginners often write tests that only call functions without checking the result. That does not prove much.

Every test should end by checking state, an event, a returned value, or a revert. Also take compiler warnings seriously. A repo with warnings looks unfinished.