You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: operatingsystem_linux_test.go
    path of file: ./repos/docker-ce/components/engine/pkg/parsers/operatingsystem
    
    the code of the file until where you have to start completion: //go:build linux || freebsd
// +build linux freebsd

package operatingsystem // import "github.com/docker/docker/pkg/parsers/operatingsystem"

import (
	"os"
	"path/filepath"
	"testing"

	"gotest.tools/v3/assert"
)

type EtcReleaseParsingTest struct {
	name        string
	content     string
	expected    string
	expectedErr string
}

func TestGetOperatingSystem(t *testing.T) {
	tests := []EtcReleaseParsingTest{
		{
			content: `NAME="Ubuntu"
PRETTY_NAME_AGAIN="Ubuntu 14.04.LTS"
V
    
func TestGetOperatingSystemVersion(t *testing.T) {
	tests := []EtcReleaseParsingTest{
		{
			name: "ubuntu 14.04",
			content: `NAME="Ubuntu"
PRETTY_NAME="Ubuntu 14.04.LTS"
VERSION="14.04, Trusty Tahr"
ID=ubuntu
ID_LIKE=debian
VERSION_ID="14.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"`,
			expected: "14.04",
		},
		{
			name: "gentoo",
			content: `NAME=Gentoo
ID=gentoo
PRETTY_NAME="Gentoo/Linux"
ANSI_COLOR="1;32"
HOME_URL="http://www.gentoo.org/"
SUPPORT_URL="http://www.gentoo.org/main/en/support.xml"
BUG_REPORT_URL="https://bugs.gentoo.org/"
`,
		},
		{
			name: "dual version id",
			content: `VERSION_ID="14.04"
VERSION_ID=18.04`,
			expected: "18.04",
		},
	}

	runEtcReleaseParsingTests(t, tests, GetOperatingSystemVersion)
}