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: domainxml_internal_test.go
    path of file: ./repos/juju/container/kvm/libvirt
    
    the code of the file until where you have to start completion: // Copyright 2016 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.

package libvirt

import (
	"github.com/juju/testing"
	jc "github.com/juju/testing/checkers"
	gc "gopkg.in/check.v1"
)

// gocheck boilerplate.
type domainXMLInternalSuite struct {
	testing.IsolationSuite
}

var _ = gc.Suite(&domainXMLInternalSuite{})

func (domainXMLInternalSuite) TestDeviceID(
    
func (domainXMLInternalSuite) TestDeviceID(c *gc.C) {
	table := []struct {
		in     int
		want   string
		errMsg string
	}{
		{0, "vda", ""},
		{4, "vde", ""},
		{15, "vdp", ""},
		{25, "vdz", ""},
		{-1, "", "got -1 but only support devices 0-25"},
		{26, "", "got 26 but only support devices 0-25"},
		{120, "", "got 120 but only support devices 0-25"},
	}
	for i, test := range table {
		c.Logf("test %d for input %d", i+1, test.in)
		got, err := deviceID(test.in)
		if err != nil {
			c.Check(err, gc.ErrorMatches, test.errMsg)
			c.Check(got, gc.Equals, "")
			continue
		}
		c.Check(got, gc.Equals, test.want)
		c.Check(err, jc.ErrorIsNil)
	}
}