Coverage and Gas Reports

Two metrics help judge contract quality:

• Code coverage — how much of your Solidity is exercised by tests.
• Gas usage — how expensive your functions are to call.

Both are available as Hardhat plugins, and the Toolbox includes the gas reporter.

Coverage measures the percentage of statements, branches, and functions touched by your tests.

• Low coverage means untested code paths — potential hidden bugs.
• 100% coverage does not guarantee correctness, but gaps are red flags.