Day 16 – Advanced Foundry Today I completed the full DeFi protocol project and tied together everything built over the past couple of weeks. 🟣 Finished implementing the remaining core protocol logic 🟣 Reviewed the system end-to-end: collateral, minting, liquidation, and invariants 🟣 Refined protocol flows to match real DeFi behavior 🟣 Strengthened confidence reading and reasoning about a full production-scale codebase 🟣 Identified remaining test cases to be written for deeper coverage and edge scenarios Big takeaway: Finishing a protocol is only half the job — proving it’s safe is where real work begins. Wrapping up implementation, next focus is hardening the test suite #BuildInPublic #Web3 #DeFi #Solidity #Foundry #InvariantTesting #Cyfrin #SmartContracts

Day 15 – Advanced Foundry Today was all about invariant testing and fuzzing at protocol scale: one of the most important (and hardest) parts of DeFi development. 🟣 Built a stateful fuzz testing Handler for invariant testing in Foundry. 🟣 Extended handlers to support deposit collateral flows. 🟣 Implemented redeem collateral handlers to test withdrawal paths. 🟣 Added a mint handler to simulate realistic user behavior. 🟣 Debugged failing invariant tests and learned how to reason about fuzz failures. 🟣 Gained hands-on experience diagnosing issues caused by price feeds and state transitions. Big takeaway: Invariant testing doesn’t tell you what broke — it forces you to understand why the protocol broke. This really shifted my mindset from “writing tests” to proving protocol safety under chaos #BuildInPublic #Web3 #DeFi #Solidity #Foundry #FuzzTesting #InvariantTesting #Cyfrin #SmartContracts

InvariantTesting and extreme edge case fuzzing with real world example, thank you very much in advance ser! 🫡