Audit Everything<\/p>\n
The first time a test destroyed my \u201cperfect\u201d smart contract, it wasn\u2019t a hacker. It was my own dev environment. I had just finished an AI\u2011assisted Solidity contract. Clean code. No compiler warnings. A few happy\u2011path tests\u00a0passing.<\/p>\n
Then I switched frameworks, hit one command\u2026 and watched a fuzz test tear it apart. Same contract. Same logic. Different tools.<\/p>\n
That\u2019s when it\u00a0clicked:<\/p>\n
How<\/em> you develop and test your contracts (Hardhat, Foundry, static analyzers) matters almost as much as what you write. By now in this series,\u00a0you\u2019ve:<\/p>\n Written and deployed simple contracts.Seen how bugs like reentrancy can drain real\u00a0money.Watched AI generate \u201cworking\u201d Solidity that still hides security\u00a0traps.<\/p>\n The current\u00a0reality:<\/p>\n Smart contract exploits still cost users hundreds of millions each\u00a0year.Security standards like the OWASP Smart Contract Top 10 and audit firm guides push for tests, fuzzing, and static analysis<\/strong>, not just \u201cit compiles.\u201dMost serious teams use some mix\u00a0of:A dev framework (Hardhat \/\u00a0Foundry)Automated tests (unit, integration, fuzz)Static analysis tools (Slither, Aderyn)<\/p>\n So if you\u2019re learning Web3 today, you\u2019re not just learning Solidity syntax. You\u2019re learning a workflow<\/strong>.<\/p>\n Hardhat has been one of the default Ethereum dev tools for years, and it\u2019s still heavily\u00a0used.<\/p>\n Think of Hardhat as your full\u2011stack dev companion<\/strong>:<\/p>\n You write tests and scripts in JavaScript or TypeScript.You deploy contracts, fork mainnet, run tasks, and hook into frontend\u00a0tooling.You get a big plugin ecosystem (Ethers.js, OpenZeppelin, gas reporters, coverage, etc.).<\/p>\n Why beginners and product teams love\u00a0it:<\/p>\n If you come from web2 or React, JS\/TS tests feel\u00a0natural.It plays nicely with infra like MetaMask, Alchemy, and\u00a0Infura.You can simulate real user flows using mainnet forking in local\u00a0tests.<\/p>\n Weak spots:<\/p>\n Tests live in JS\/TS while contracts live in Solidity. That context switch makes some people\u00a0slower.Fuzzing and advanced testing are usually plugin\u2011based rather than built\u2011in.<\/p>\n Hardhat shines\u00a0when:<\/p>\n You\u2019re building a dApp with a frontend.You want rich tooling and integrations.You think in \u201cproduct flows\u201d as much as \u201craw Solidity.\u201d<\/p>\n Foundry has quickly become a favorite for Solidity\u2011heavy and security\u2011minded work.<\/p>\n Think of Foundry as your high\u2011performance testing and security\u00a0rig<\/strong>:<\/p>\n You write tests directly in Solidity.You run them with forge\u00a0test.You get built\u2011in fuzzing, invariant tests, cheatcodes, and very fast compile\u00a0times.<\/p>\n Key advantages:<\/p>\n Speed<\/strong>: Benchmarks show Foundry compiling and running tests several times faster than traditional JS\u2011based\u00a0setups.Solidity\u2011first<\/strong>: No JS\/TS layer; your tests are contracts. You stay in one language and think like the\u00a0EVM.Security\u2011friendly<\/strong>: Fuzzing and invariants are first\u2011class, which is exactly what modern security guides recommend.<\/p>\n Why this matters after your last articles:<\/p>\n When you\u2019re reviewing AI\u2011generated contracts, fuzz tests can hit weird inputs you would never think\u00a0of.When you\u2019re worried about reentrancy or logic bugs, invariants help you say: \u201cNo matter what inputs the fuzzer tries, total balances never go negative.\u201d<\/p>\n Foundry shines\u00a0when:<\/p>\n You care deeply about Solidity correctness and security.You\u2019re okay living mostly in Solidity.You want to iterate on tests and contracts fast<\/strong>.<\/p>\n For most builders, the honest answer is often: both<\/strong>, depending on the\u00a0job.<\/p>\n Use this mental\u00a0model:<\/p>\n Hardhat<\/strong> = Product and integration focus<\/p>\n JS\/TS tests, mainnet forking, plugin ecosystem, frontend\/devops integrations.<\/p>\n Foundry<\/strong> = Solidity and security\u00a0focus<\/p>\n Fast compile\/test loop, Solidity tests, built\u2011in fuzzing & invariants.<\/p>\n You don\u2019t have to marry one tool\u00a0forever.<\/p>\n You can prototype and test core logic with\u00a0Foundry.Then use Hardhat for deployment scripts, mainnet forks, and frontend integration.<\/p>\n For this 60\u2011day\u00a0journey:<\/p>\n If you\u2019re just getting comfortable with Solidity, starting with Foundry tests can actually teach you more Solidity<\/strong>\u00a0faster.If you\u2019re more comfortable in JS\/TS, Hardhat is a gentle on\u2011ramp into smart contracts.<\/p>\n The real mistake isn\u2019t picking the \u201cwrong\u201d framework. On the last article, A medium follower, MihaiHng commented<\/a>:<\/p>\n \u201cBesides manual review checking for the CEI pattern to be respected, there are some static analysis tools that are very helpful, like Slither,\u00a0Aderyn.\u201d<\/em><\/p>\n He\u2019s absolutely right.<\/p>\n Manual review + CEI is important\u2026 That\u2019s where static analyzers come\u00a0in:<\/p>\n Slither<\/strong> (by Trail of\u00a0Bits)<\/p>\n One of the most widely used Solidity static analysis\u00a0tools.Detects common vulnerabilities (including reentrancy, access control issues, and dangerous patterns) quickly.Integrates nicely into CI and with both Hardhat and Foundry projects.<\/p>\n Aderyn<\/strong> (by\u00a0Cyfrin)<\/p>\n A modern static analyzer focused on Solidity projects.Has first\u2011class support for Foundry and Hardhat\u00a0layouts.Can generate reports in JSON\/Markdown\/SARIF and plugs into VS Code for in\u2011editor feedback.<\/p>\n In a realistic workflow:<\/p>\n You write tests in Hardhat or\u00a0Foundry.You run fuzzing\/invariants for deeper coverage.You also<\/strong> run Slither\/Aderyn to catch patterns humans and tests might\u00a0miss.<\/p>\n Here\u2019s a lightweight process you can actually run on your next contract:<\/p>\n Prototype<\/strong><\/p>\n Use AI (carefully) plus your own edits to draft the Solidity.Keep contracts small and\u00a0focused.<\/p>\n Pick a framework<\/strong><\/p>\n If you\u2019re in JS land: Hardhat project, JS\/TS\u00a0tests.If you\u2019re in Solidity land: Foundry project, Solidity\u00a0tests.<\/p>\n Write basic\u00a0tests<\/strong><\/p>\n Happy\u2011path unit tests: deposits, withdrawals, state\u00a0changes.A few \u201cannoying user\u201d cases (zero values, big values, repeated\u00a0calls).<\/p>\n Add fuzzing \/ invariants<\/strong><\/p>\n In Foundry: use built\u2011in fuzz tests and invariants.In Hardhat: add fuzzing via plugins or external tools if\u00a0needed.<\/p>\n Run static\u00a0analysis<\/strong><\/p>\n Slither: quick scan for known bug patterns.Aderyn: extra detectors plus better integration with modern\u00a0stacks.<\/p>\n Only then think about testnet \/\u00a0mainnet<\/strong><\/p>\n After tests + fuzzing + static analysis are green, deploy to a testnet (like Sepolia).Share the address with your community for more\u00a0eyes.<\/p>\n This is the kind of workflow audit firms and serious teams expect\u00a0now.<\/p>\n The question isn\u2019t \u201cHardhat or Foundry?\u201d \u201cHow many layers of safety am I putting between my code and mainnet?\u201d<\/strong><\/p>\n Hardhat gives you rich JS\/TS tooling and real\u2011world flows. Use whichever mix helps\u00a0you:<\/p>\n Ship faster and<\/em>\u00a0safer.Catch AI\u2011introduced bugs before attackers do.Build the habits real Web3 teams already expect from a developer or\u00a0DevRel.<\/p>\n Because in the end, no one will remember which framework you\u00a0used.<\/p>\n They\u2019ll remember whether your contracts stayed safe when it mattered.<\/p>\n Today\u2019s article zoomed out and\u00a0asked:<\/p>\n \u201cHow do real\u2011world teams actually develop<\/em> and test<\/em> smart contracts?\u201d<\/p>\n Tomorrow, the plan is to zoom back in and do this end\u2011to\u2011end on a real contract<\/strong>:<\/p>\n Take a small AI\u2011generated Solidity contract.Wrap it in a Foundry\u00a0project.Add a handful of tests, then fuzzing and an invariant.Run Slither or Aderyn once and see what they catch before any testnet\u00a0deploy.<\/p>\n Think of today as the map of the territory.<\/p>\n Tomorrow, we\u2019ll walk a full path through it together, step by\u00a0step.<\/p>\n \ud83d\udd17 Solidity Docs\u200a\u2014\u200aSecurity Considerations<\/a> \ud83d\udd17 ConsenSys Diligence\u200a\u2014\u200aSmart Contract Best Practices<\/a> \ud83d\udd17 OpenZeppelin Contracts\u200a\u2014\u200aReentrancyGuard<\/a> \ud83d\udd17 Foundry Documentation<\/a> Follow the series on Medium<\/a> | Twitter<\/a> |\u00a0Future<\/a><\/p>\n Jump into Web3ForHumans<\/a> on Telegram and let\u2019s build together.<\/p>\n The Test That Broke My \u201cPerfect\u201d Contract<\/a> was originally published in Coinmonks<\/a> on Medium, where people are continuing the conversation by highlighting and responding to this story.<\/p>","protected":false},"excerpt":{"rendered":" Audit Everything The first time a test destroyed my \u201cperfect\u201d smart contract, it wasn\u2019t a hacker. It was my own dev environment. I had just finished an AI\u2011assisted Solidity contract. Clean code. No compiler warnings. A few happy\u2011path tests\u00a0passing. Then I switched frameworks, hit one command\u2026 and watched a fuzz test tear it apart. Same […]<\/p>\n","protected":false},"author":0,"featured_media":127613,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-127612","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-interesting"],"_links":{"self":[{"href":"https:\/\/mycryptomania.com\/index.php?rest_route=\/wp\/v2\/posts\/127612"}],"collection":[{"href":"https:\/\/mycryptomania.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mycryptomania.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/mycryptomania.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=127612"}],"version-history":[{"count":0,"href":"https:\/\/mycryptomania.com\/index.php?rest_route=\/wp\/v2\/posts\/127612\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mycryptomania.com\/index.php?rest_route=\/wp\/v2\/media\/127613"}],"wp:attachment":[{"href":"https:\/\/mycryptomania.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=127612"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mycryptomania.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=127612"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mycryptomania.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=127612"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
This is Day 31 of the 60\u2011Day Web3\u00a0journey<\/strong>.<\/p>\nWhy Dev Tools Matter More\u00a0Now<\/h3>\n
Hardhat\u200a\u2014\u200aThe JavaScript Sidekick<\/h3>\n
Foundry\u200a\u2014\u200aThe Solidity\u2011Native Power\u00a0Tool<\/h3>\n
So\u2026 Hardhat or\u00a0Foundry?<\/h3>\n
It\u2019s not using any framework seriously<\/strong> and relying only on Remix +\u00a0hope.<\/p>\nWhere Slither and Aderyn\u00a0Fit:<\/h3>\n
\u2026but modern security culture assumes you will miss\u00a0things<\/strong>.<\/p>\nA Dev Workflow You Can\u00a0Copy<\/h3>\n
Key Takeaway<\/h3>\n
It\u2019s:<\/p>\n
Foundry gives you speed, Solidity\u2011native tests, fuzzing, and invariants.
Slither and Aderyn give you automated eyes that never get\u00a0tired.<\/p>\nWhat\u2019s Coming\u00a0Next<\/h3>\n
Resources to Go\u00a0Deeper<\/h3>\n
Official language docs explaining why external calls are dangerous and how to structure state changes\u00a0safely.<\/p>\n
Classic reference for the attack pattern, checks\u2011effects\u2011interactions, and common pitfalls.<\/p>\n
The de\u2011facto standard implementation of a reentrancy lock; perfect for understanding how to actually use the\u00a0pattern.<\/p>\n
Complete guide to installing, testing with fuzz, invariants, and cheatcodes.<\/p>\n