🧠 Intro
I recently built a Token Sale + Vesting system in Solidity. Like most devs on a roll, I thought:

“Let me finish all the contracts first, then write the tests at the end.”

Bad idea. Here's what happened — and what I learned the hard way.

🔥 What Went Wrong
When I finally got to testing, things started breaking everywhere.

Random reverts on function calls

OwnableUnauthorizedAccount errors

Division by zero panics

Logic bugs that I didn’t notice while coding

It was overwhelming. The error messages weren’t always obvious, and debugging took forever because I wasn’t sure which contract was causing the issue.

🧪 The Turning Point
I decided to step back and test each contract in isolation, one at a time.

✅ First I wrote tests just for the Vesting contract
✅ Then I tested the TokenSale contract independently
✅ Finally, I tested how they interacted

Suddenly everything made more sense. I found the root of most bugs easily and could confidently refactor parts of the logic.

🛠️ Key Takeaways
If you're working on a Web3/Smart Contract project, I highly recommend this approach:

Test each contract right after writing it

Catch issues while they're fresh in your mind

Start with unit tests before integration tests

Test the contract alone first

Simulate edge cases early

Like caps not met, wrong owner calling, or time not yet passed

✍️Final Thoughts
I’m still learning, but this experience was a big eye-opener. Testing smart contracts isn’t just about coverage — it’s about clarity and confidence.

If you’re working on your own Solidity projects, trust me:
Test early. It’s worth it.

🏷️ Tags

web3 #solidity #testing #foundry #smartcontracts #blockchain #learning