How to Measure Code Coverage of Isolated Folders in Go

In Go, measuring code coverage for packages residing in separate folders can prove challenging. Consider the following project structure:

stuff/stuff.go -> package: stuff
test/stuff/stuff_test.go -> package: test

Even though stuff_test.go executes code from stuff.go, the coverage report may indicate:

coverage: 0.0% of statements

This is because go test -cover by default analyzes only the package being tested, not its dependencies.

To address this issue, you can use the -coverpkg option to specify which packages should be considered for coverage analysis. For example, the following command will include all packages under the current directory:

go test ./test/... -coverprofile=cover.out -coverpkg ./...

Once the test execution is complete, you can generate a coverage report using:

go tool cover -html=cover.out

This will provide a detailed report of the code coverage for your project, including the coverage of packages in separate folders.