It provides a way for testing private function in Go

export_test.go

package service

var CalculateSum = calculateSum

service.go

package service

func calculateSum(a, b int) int {
	return a + b
}

service_test.go

package service_test

import (
	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"
	service "github.com/yulintan/test-private-function"
)

var _ = Describe("myService", func() {
	It("returns the sum", func() {
		r := service.CalculateSum(1, 2)
		Expect(r).To(Equal(3))
	})
})