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: usage_test.go
    path of file: ./repos/go-arg
    
    the code of the file until where you have to start completion: package arg

import (
	"bytes"
	"errors"
	"fmt"
	"os"
	"strings"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

type NameDotName struct {
	Head, Tail string
}

func (n *NameDotName) UnmarshalText(b []byte) error {
	s := string(b)
	pos := strings.Index(s, ".")
	if pos == -1 {
		return fmt.Errorf("missing period in %s", s)
	}
	n.Head = s[:pos]
	n.Tail = s[pos+1:]
	return nil
}

func (n *NameDotName) MarshalText() (text []byte, err error) {
	text = []byte(fmt.Sprintf("%s.%s", n.Head, n.Tail))
	return
}

func TestWriteUsage(t *testing.T) {
	expectedUsage := "Usage: exampl
    
func TestUsageWithDefaults(t *testing.T) {
	expectedUsage := "Usage: example [--label LABEL] [--content CONTENT]"

	expectedHelp := `
Usage: example [--label LABEL] [--content CONTENT]

Options:
  --label LABEL [default: cat]
  --content CONTENT [default: dog]
  --help, -h             display this help and exit
`
	var args struct {
		Label   string
		Content string `default:"dog"`
	}
	args.Label = "cat"
	p, err := NewParser(Config{Program: "example"}, &args)
	require.NoError(t, err)

	args.Label = "should_ignore_this"

	var help bytes.Buffer
	p.WriteHelp(&help)
	assert.Equal(t, expectedHelp[1:], help.String())

	var usage bytes.Buffer
	p.WriteUsage(&usage)
	assert.Equal(t, expectedUsage, strings.TrimSpace(usage.String()))
}