I’ve written a ton of tests in golang without properly knowing about the -coverprofile flag and how it can be used to visualize parts of code that aren’t covered in unit tests.

That being said, I did know about the -cover flag that helped me get a conventional idea of code coverage in my unit tests (in %). So, I’m documenting how this can be done without any external dependencies.

To visualize coverage reports while running go test for a particular package:

1. Run tests, generate a raw coverage report & store it inside a .out file, for instance,

go test -coverprofile=toolbox.out ./toolbox

2. Generate coverage report in terms of lines of code, for example,

go tool cover -html=toolbox.out

Doing so will generate and open a temporary coverage.html file with colour-coded code coverage information!

This tool could help programmers gain back a ton of time in dev-loops. Hope you found this helpful!

👋 ⸻ @TnvMadhav