How to Generate Go Coverage in CI

go test -coverprofile writes a coverage profile that go tool cover turns into a percentage or HTML.

Run go test ./... -coverprofile=coverage.out -covermode=atomic, then go tool cover -func=coverage.out to print the total. The .out profile is what upload tools consume.

Steps

• Run go test ./... -coverprofile=coverage.out -covermode=atomic.
• Print the total with go tool cover -func=coverage.out.
• Upload coverage.out or convert it as needed.

Terminal

go test ./... -race -covermode=atomic -coverprofile=coverage.out
go tool cover -func=coverage.out | tail -n 1

Gotchas

• Use -covermode=atomic when running with -race; set mode is not safe under concurrency.
• By default coverage counts only the package under test; add -coverpkg=./... to count cross-package usage.

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