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: config_test.go
    path of file: ./repos/gluetun/internal/wireguard
    
    the code of the file until where you have to start completion: package wireguard

import (
	"errors"
	"net"
	"net/netip"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
)

func Test_makeDeviceConfig(t *testing.T) {
	t.Parallel()

	const (
		validKey1 = "oMNSf/zJ0pt1ciy+qIRk8Rlyfs9accwuRLnKd85Yl1Q="
		validKey2 = "aPjc9US5ICB30D1P4glR9tO7bkB2Ga+KZiFqnoypBHk="
		validKey3 = "gFIW0lTmBYEucynoIg+XmeWckDUXTcC4Po5ijR5G+HM="
	)

	parseKey := func(t *testing.T, s string) *wgtypes.Key {
		t.Helper()
		key, err := wgtypes.ParseKey(s)
		require.NoError(t, err)
		return &key
	}

	intPtr := func(n int) *int { return &n }

	testCases := map[string]struct {
		settings Settings
		config   wgtypes.Config
		err      error
	}{
		"bad private key": {
			settings: Settings{
				PrivateKey: "bad key",
			},
			err: ErrPrivateKeyInvalid,
		},
		"bad public key": {
			settings: Settings{
				PrivateKey: validKey1,
				PublicKey:  "bad key",
			},
			err: errors.New("cannot parse public key: bad key"),
		},
		"bad pre-shared key": {
			settings: Settings{
				PrivateKey:   validKey1,
				PublicKey:    validKey2,
				PreSharedKey: "bad key",
			},
			err: errors.New("cannot parse pre-shared key"),
		},
		"valid settings": {
			settings: Settings{
				PrivateKey:   validKey1,
				PublicKey:    validKey2,
				PreSharedKey: validKey3,
				FirewallMark: 9876,
				Endpoint:     netip.AddrPortFrom(netip.AddrFrom4([4]byte{99, 99, 99, 99}), 51820),
			},
			config: wgtypes.Config{
				PrivateKey:   parseKey(t, validKey1),
				ReplacePeers: true,
				Fi
    
func Test_makeDeviceConfig(t *testing.T) {
	t.Parallel()

	const (
		validKey1 = "oMNSf/zJ0pt1ciy+qIRk8Rlyfs9accwuRLnKd85Yl1Q="
		validKey2 = "aPjc9US5ICB30D1P4glR9tO7bkB2Ga+KZiFqnoypBHk="
		validKey3 = "gFIW0lTmBYEucynoIg+XmeWckDUXTcC4Po5ijR5G+HM="
	)

	parseKey := func(t *testing.T, s string) *wgtypes.Key {
		t.Helper()
		key, err := wgtypes.ParseKey(s)
		require.NoError(t, err)
		return &key
	}

	intPtr := func(n int) *int { return &n }

	testCases := map[string]struct {
		settings Settings
		config   wgtypes.Config
		err      error
	}{
		"bad private key": {
			settings: Settings{
				PrivateKey: "bad key",
			},
			err: ErrPrivateKeyInvalid,
		},
		"bad public key": {
			settings: Settings{
				PrivateKey: validKey1,
				PublicKey:  "bad key",
			},
			err: errors.New("cannot parse public key: bad key"),
		},
		"bad pre-shared key": {
			settings: Settings{
				PrivateKey:   validKey1,
				PublicKey:    validKey2,
				PreSharedKey: "bad key",
			},
			err: errors.New("cannot parse pre-shared key"),
		},
		"valid settings": {
			settings: Settings{
				PrivateKey:   validKey1,
				PublicKey:    validKey2,
				PreSharedKey: validKey3,
				FirewallMark: 9876,
				Endpoint:     netip.AddrPortFrom(netip.AddrFrom4([4]byte{99, 99, 99, 99}), 51820),
			},
			config: wgtypes.Config{
				PrivateKey:   parseKey(t, validKey1),
				ReplacePeers: true,
				FirewallMark: intPtr(9876),
				Peers: []wgtypes.PeerConfig{
					{
						PublicKey:    *parseKey(t, validKey2),
						PresharedKey: parseKey(t, validKey3),
						AllowedIPs: []net.IPNet{
							{
								IP:   net.IPv4(0, 0, 0, 0),
								Mask: []byte{0, 0, 0, 0},
							},
							{
								IP:   net.IPv6zero,
								Mask: []byte(net.IPv6zero),
							},
						},
						ReplaceAllowedIPs: true,
						Endpoint: &net.UDPAddr{
							IP:   net.IP{99, 99, 99, 99},
							Port: 51820,
						},
					},
				},
			},
		},
	}

	for name, testCase := range testCases {
		testCase := testCase
		t.Run(name, func(t *testing.T) {
			t.Parallel()

			config, err := makeDeviceConfig(testCase.settings)

			if testCase.err != nil {
				require.Error(t, err)
				assert.Equal(t, testCase.err.Error(), err.Error())
			} else {
				assert.NoError(t, err)
			}

			assert.Equal(t, testCase.config, config)
		})
	}
}