package oci

import (
	"context"
	"io/ioutil"
	"os"
	"testing"

	"github.com/docker/docker/libnetwork/resolvconf"
	"github.com/stretchr/testify/require"
)

// TestResolvConfNotExist modifies a global variable
// It must not run in parallel.
func TestResolvConfNotExist(t *testing.T) {
	oldResolvconfGet := resolvconfGet
	defer func() {
		resolvconfGet = oldResolvconfGet
	}()
	resolvconfGet = func() (*resolvconf.File, error) {
		return nil, os.ErrNotExist
	}

	defaultResolvConf := `
nameserver 8.8.8.8
nameserver 8.8.4.4
nameserver 2001:4860:4860::8888
nameserver 2001:4860:4860::8844`

	dir, err := ioutil.TempDir("", "buildkit-test")
	require.NoError(t, err)
	defer os.RemoveAll(dir)
	ctx := context.Background()
	p, err := GetResolvConf(ctx, dir, nil, nil)
	require.NoError(t, err)
	b, err := ioutil.ReadFile(p)
	require.NoError(t, err)
	require.Equal(t, string(b), defaultResolvConf)
}