}

-- pkg_test.go --
package pkg

import "runtime"

func PrintFileForTest() {
	_, file, _, _ := runtime.Caller(0)
	println(file)
}

-- pkg_x_test.go --
package pkg_test

import (
	"runtime"
	"testing"

	"example.com/pkg"
)

func TestMain(m *testing.M) {
	pkg.PrintFile()
	pkg.PrintFileForTest()
	PrintFileInXTest()
}

func PrintFileInXTest() {

	println(file)
}

-- main_test.go --
package main

import (
	"runtime"
	"testing"
)

func PrintFileForTest() {
	_, file, _, _ := runtime.Caller(0)
	println(file)
}

func TestMain(m *testing.M) {
	PrintFile()
	PrintFileForTest()

}

-- pkg_x_test.go --
package pkg_test_test

import (
	"runtime"
	"testing"

	"example.com/pkg_test"
)

func PrintFileForTest() {
	_, file, _, _ := runtime.Caller(0)
	println(file)
}

func TestMain(m *testing.M) {
	pkg_test.PrintFile()
	PrintFileForTest()