Capturing Code Coverage from a Go Binary

When running unit tests, capturing code coverage is straightforward. However, gathering coverage metrics during integration tests against the binary itself can prove challenging. Is there a way to overcome this hurdle?

The Need for Integration Test Coverage

Integration tests provide a more comprehensive view of code coverage than unit tests alone. By running the binary against real-world inputs, we can assess how our code behaves under various conditions.

The Challenge

The Go coverage tool operates only in conjunction with the testing package. This poses an issue for integration tests that typically don't fit within this framework.

The Solution: Integration Tests in Go's Testing Framework

To capture coverage from integration tests, we need to integrate them into the testing package somehow.

1. Create a Test File: Create a test file that executes your main() function in a goroutine.

func TestMainApp(t *testing.T) {
    go main()
    // ... Start integration tests here
}

2. Execute Integration Tests: Use exec.Cmd to run your integration tests outside the goroutine created earlier.
3. Gather Coverage Statistics: Finally, gather the coverage statistics using the coverage tool.

Other Resources

For a previous discussion on this topic, refer to the article "Go coverage with external tests," which explores a comparable approach.