func TestCharsetControlDetect(t *testing.T) {
	input := "=?US\nASCII?Q?Keith_Moore?="
	expect := input
	result := DecodeHeader(input)
	assert.Equal(t, expect, result)
}
Test control character detection & abort
package enmime
import (
	"testing"
	"github.com/stretchr/testify/assert"
)
func TestPlainSingleToken(t *testing.T) {
	input := "Test"
	expect := input
	result := DecodeHeader(input)
	assert.Equal(t, expect, result)
}
func TestPlainTokens(t *testing.T) {
	input := "Testing One two 3 4"
	expect := input
	result := DecodeHeader(input)
	assert.Equal(t, expect, result)
}