Testing & Debugging

Testing is essential — smart contract bugs can lose millions of dollars.

Development Frameworks:
• Hardhat — The most popular Ethereum development environment. Supports TypeScript, has a built-in local blockchain, and great debugging tools.
• Foundry — Fast, Solidity-native testing framework. Write tests in Solidity itself.

Writing Tests:
1. Deploy the contract to a local test network
2. Call functions and verify expected outcomes
3. Test edge cases: zero amounts, unauthorized callers, overflow scenarios
4. Test revert conditions to make sure invalid inputs are rejected

Gas Optimization:
• Use uint256 instead of smaller integers (the EVM operates on 256-bit words)
• Batch operations when possible
• Use events instead of storage for data only needed off-chain
• Minimize external contract calls

Debugging: Hardhat’s console.log works inside Solidity during development. Use it to trace execution flow and inspect variables.

Always test on a testnet (like Avalanche Fuji) before deploying to mainnet.