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Foundry forge coverage

Updated: Apr 10, 2023

Visual line coverage report with LCOV

forge coverage lcov report

If you run "forge coverage" in a foundry project, you'll get a table showing how much of your lines and branches are covered.

foundry forge coverage

If you want to see visually which lines and branches are or are not covered, use the following steps

Instructions to get line visual coverage in foundry

1. Install genhtml

brew install genhtml

2. Create a coverage directory in your foundry project

mkdir coverage

3. Run the following command

forge coverage --report lcov && genhtml --branch-coverage --output-dir coverage

4. Open the following file


And you'll be able to see a coverage report like what you see at the top of the page.

No available formula with the name "genhtml". Did you mean ekhtml?

If you get this error, do

brew install ekhtml

and it will install genhtml.


This tutorial was created by Matteo Vendittoli, a student at the RareSkills blockchain bootcamp.

Addendum: Visual line coverage in Visual Studio Code

It is also possible to view line coverage directly inside Visual Studio Code. Credit to 0xasp_ on Twitter for sharing this with us (original tweet).

1. Install the Coverage Gutters extension in VSCode

2. Generate the coverage report

forge coverage --report lcov

3. Open the Command Palette

Pick display coverage report

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1 Comment

han tony
han tony
May 13, 2023

For genhtml, if still has some problem, can try

brew install lcov(mac)

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