cmd/stringer/golden_test.go - tools - Git at Google

 // Copyright 2014 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 // This file contains simple golden tests for various examples.
 // Besides validating the results when the implementation changes,
 // it provides a way to look at the generated code without having
 // to execute the print statements in one's head.

 package main

 import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
 	"testing"

 	"golang.org/x/tools/internal/testenv"
 )

 // Golden represents a test case.
 type Golden struct {
 	name        string
 	trimPrefix  string
 	lineComment bool
 	input       string // input; the package clause is provided when running the test.
 	output      string // expected output.
 }

 var golden = []Golden{
 	{"day", "", false, day_in, day_out},
 	{"offset", "", false, offset_in, offset_out},
 	{"gap", "", false, gap_in, gap_out},
 	{"num", "", false, num_in, num_out},
 	{"unum", "", false, unum_in, unum_out},
 	{"unumpos", "", false, unumpos_in, unumpos_out},
 	{"prime", "", false, prime_in, prime_out},
 	{"prefix", "Type", false, prefix_in, prefix_out},
 	{"tokens", "", true, tokens_in, tokens_out},
 }

 // Each example starts with "type XXX [u]int", with a single space separating them.

 // Simple test: enumeration of type int starting at 0.
 const day_in = `type Day int
 const (
 	Monday Day = iota
 	Tuesday
 	Wednesday
 	Thursday
 	Friday
 	Saturday
 	Sunday
 )
 `

 const day_out = `func _() {
 	// An "invalid array index" compiler error signifies that the constant values have changed.
 	// Re-run the stringer command to generate them again.
 	var x [1]struct{}
 	_ = x[Monday-0]
 	_ = x[Tuesday-1]
 	_ = x[Wednesday-2]
 	_ = x[Thursday-3]
 	_ = x[Friday-4]
 	_ = x[Saturday-5]
 	_ = x[Sunday-6]
 }

 const _Day_name = "MondayTuesdayWednesdayThursdayFridaySaturdaySunday"

 var _Day_index = [...]uint8{0, 6, 13, 22, 30, 36, 44, 50}

 func (i Day) String() string {
 	if i < 0 || i >= Day(len(_Day_index)-1) {
 		return "Day(" + strconv.FormatInt(int64(i), 10) + ")"
 	}
 	return _Day_name[_Day_index[i]:_Day_index[i+1]]
 }
 `

 // Enumeration with an offset.
 // Also includes a duplicate.
 const offset_in = `type Number int
 const (
 	_ Number = iota
 	One
 	Two
 	Three
 	AnotherOne = One  // Duplicate; note that AnotherOne doesn't appear below.
 )
 `

 const offset_out = `func _() {
 	// An "invalid array index" compiler error signifies that the constant values have changed.
 	// Re-run the stringer command to generate them again.
 	var x [1]struct{}
 	_ = x[One-1]
 	_ = x[Two-2]
 	_ = x[Three-3]
 }

 const _Number_name = "OneTwoThree"

 var _Number_index = [...]uint8{0, 3, 6, 11}

 func (i Number) String() string {
 	i -= 1
 	if i < 0 || i >= Number(len(_Number_index)-1) {
 		return "Number(" + strconv.FormatInt(int64(i+1), 10) + ")"
 	}
 	return _Number_name[_Number_index[i]:_Number_index[i+1]]
 }
 `

 // Gaps and an offset.
 const gap_in = `type Gap int
 const (
 	Two Gap = 2
 	Three Gap = 3
 	Five Gap = 5
 	Six Gap = 6
 	Seven Gap = 7
 	Eight Gap = 8
 	Nine Gap = 9
 	Eleven Gap = 11
 )
 `

 const gap_out = `func _() {
 	// An "invalid array index" compiler error signifies that the constant values have changed.
 	// Re-run the stringer command to generate them again.
 	var x [1]struct{}
 	_ = x[Two-2]
 	_ = x[Three-3]
 	_ = x[Five-5]
 	_ = x[Six-6]
 	_ = x[Seven-7]
 	_ = x[Eight-8]
 	_ = x[Nine-9]
 	_ = x[Eleven-11]
 }

 const (
 	_Gap_name_0 = "TwoThree"
 	_Gap_name_1 = "FiveSixSevenEightNine"
 	_Gap_name_2 = "Eleven"
 )

 var (
 	_Gap_index_0 = [...]uint8{0, 3, 8}
 	_Gap_index_1 = [...]uint8{0, 4, 7, 12, 17, 21}
 )

 func (i Gap) String() string {
 	switch {
 	case 2 <= i && i <= 3:
 		i -= 2
 		return _Gap_name_0[_Gap_index_0[i]:_Gap_index_0[i+1]]
 	case 5 <= i && i <= 9:
 		i -= 5
 		return _Gap_name_1[_Gap_index_1[i]:_Gap_index_1[i+1]]
 	case i == 11:
 		return _Gap_name_2
 	default:
 		return "Gap(" + strconv.FormatInt(int64(i), 10) + ")"
 	}
 }
 `

 // Signed integers spanning zero.
 const num_in = `type Num int
 const (
 	m_2 Num = -2 + iota
 	m_1
 	m0
 	m1
 	m2
 )
 `

 const num_out = `func _() {
 	// An "invalid array index" compiler error signifies that the constant values have changed.
 	// Re-run the stringer command to generate them again.
 	var x [1]struct{}
 	_ = x[m_2 - -2]
 	_ = x[m_1 - -1]
 	_ = x[m0-0]
 	_ = x[m1-1]
 	_ = x[m2-2]
 }

 const _Num_name = "m_2m_1m0m1m2"

 var _Num_index = [...]uint8{0, 3, 6, 8, 10, 12}

 func (i Num) String() string {
 	i -= -2
 	if i < 0 || i >= Num(len(_Num_index)-1) {
 		return "Num(" + strconv.FormatInt(int64(i+-2), 10) + ")"
 	}
 	return _Num_name[_Num_index[i]:_Num_index[i+1]]
 }
 `

 // Unsigned integers spanning zero.
 const unum_in = `type Unum uint
 const (
 	m_2 Unum = iota + 253
 	m_1
 )

 const (
 	m0 Unum = iota
 	m1
 	m2
 )
 `

 const unum_out = `func _() {
 	// An "invalid array index" compiler error signifies that the constant values have changed.
 	// Re-run the stringer command to generate them again.
 	var x [1]struct{}
 	_ = x[m_2-253]
 	_ = x[m_1-254]
 	_ = x[m0-0]
 	_ = x[m1-1]
 	_ = x[m2-2]
 }

 const (
 	_Unum_name_0 = "m0m1m2"
 	_Unum_name_1 = "m_2m_1"
 )

 var (
 	_Unum_index_0 = [...]uint8{0, 2, 4, 6}
 	_Unum_index_1 = [...]uint8{0, 3, 6}
 )

 func (i Unum) String() string {
 	switch {
 	case i <= 2:
 		return _Unum_name_0[_Unum_index_0[i]:_Unum_index_0[i+1]]
 	case 253 <= i && i <= 254:
 		i -= 253
 		return _Unum_name_1[_Unum_index_1[i]:_Unum_index_1[i+1]]
 	default:
 		return "Unum(" + strconv.FormatInt(int64(i), 10) + ")"
 	}
 }
 `

 // Unsigned positive integers.
 const unumpos_in = `type Unumpos uint
 const (
 	m253 Unumpos = iota + 253
 	m254
 )

 const (
 	m1 Unumpos = iota + 1
 	m2
 	m3
 )
 `

 const unumpos_out = `func _() {
 	// An "invalid array index" compiler error signifies that the constant values have changed.
 	// Re-run the stringer command to generate them again.
 	var x [1]struct{}
 	_ = x[m253-253]
 	_ = x[m254-254]
 	_ = x[m1-1]
 	_ = x[m2-2]
 	_ = x[m3-3]
 }

 const (
 	_Unumpos_name_0 = "m1m2m3"
 	_Unumpos_name_1 = "m253m254"
 )

 var (
 	_Unumpos_index_0 = [...]uint8{0, 2, 4, 6}
 	_Unumpos_index_1 = [...]uint8{0, 4, 8}
 )

 func (i Unumpos) String() string {
 	switch {
 	case 1 <= i && i <= 3:
 		i -= 1
 		return _Unumpos_name_0[_Unumpos_index_0[i]:_Unumpos_index_0[i+1]]
 	case 253 <= i && i <= 254:
 		i -= 253
 		return _Unumpos_name_1[_Unumpos_index_1[i]:_Unumpos_index_1[i+1]]
 	default:
 		return "Unumpos(" + strconv.FormatInt(int64(i), 10) + ")"
 	}
 }
 `

 // Enough gaps to trigger a map implementation of the method.
 // Also includes a duplicate to test that it doesn't cause problems
 const prime_in = `type Prime int
 const (
 	p2 Prime = 2
 	p3 Prime = 3
 	p5 Prime = 5
 	p7 Prime = 7
 	p77 Prime = 7 // Duplicate; note that p77 doesn't appear below.
 	p11 Prime = 11
 	p13 Prime = 13
 	p17 Prime = 17
 	p19 Prime = 19
 	p23 Prime = 23
 	p29 Prime = 29
 	p37 Prime = 31
 	p41 Prime = 41
 	p43 Prime = 43
 )
 `

 const prime_out = `func _() {
 	// An "invalid array index" compiler error signifies that the constant values have changed.
 	// Re-run the stringer command to generate them again.
 	var x [1]struct{}
 	_ = x[p2-2]
 	_ = x[p3-3]
 	_ = x[p5-5]
 	_ = x[p7-7]
 	_ = x[p77-7]
 	_ = x[p11-11]
 	_ = x[p13-13]
 	_ = x[p17-17]
 	_ = x[p19-19]
 	_ = x[p23-23]
 	_ = x[p29-29]
 	_ = x[p37-31]
 	_ = x[p41-41]
 	_ = x[p43-43]
 }

 const _Prime_name = "p2p3p5p7p11p13p17p19p23p29p37p41p43"

 var _Prime_map = map[Prime]string{
 	2:  _Prime_name[0:2],
 	3:  _Prime_name[2:4],
 	5:  _Prime_name[4:6],
 	7:  _Prime_name[6:8],
 	11: _Prime_name[8:11],
 	13: _Prime_name[11:14],
 	17: _Prime_name[14:17],
 	19: _Prime_name[17:20],
 	23: _Prime_name[20:23],
 	29: _Prime_name[23:26],
 	31: _Prime_name[26:29],
 	41: _Prime_name[29:32],
 	43: _Prime_name[32:35],
 }

 func (i Prime) String() string {
 	if str, ok := _Prime_map[i]; ok {
 		return str
 	}
 	return "Prime(" + strconv.FormatInt(int64(i), 10) + ")"
 }
 `

 const prefix_in = `type Type int
 const (
 	TypeInt Type = iota
 	TypeString
 	TypeFloat
 	TypeRune
 	TypeByte
 	TypeStruct
 	TypeSlice
 )
 `

 const prefix_out = `func _() {
 	// An "invalid array index" compiler error signifies that the constant values have changed.
 	// Re-run the stringer command to generate them again.
 	var x [1]struct{}
 	_ = x[TypeInt-0]
 	_ = x[TypeString-1]
 	_ = x[TypeFloat-2]
 	_ = x[TypeRune-3]
 	_ = x[TypeByte-4]
 	_ = x[TypeStruct-5]
 	_ = x[TypeSlice-6]
 }

 const _Type_name = "IntStringFloatRuneByteStructSlice"

 var _Type_index = [...]uint8{0, 3, 9, 14, 18, 22, 28, 33}

 func (i Type) String() string {
 	if i < 0 || i >= Type(len(_Type_index)-1) {
 		return "Type(" + strconv.FormatInt(int64(i), 10) + ")"
 	}
 	return _Type_name[_Type_index[i]:_Type_index[i+1]]
 }
 `

 const tokens_in = `type Token int
 const (
 	And Token = iota // &
 	Or               // |
 	Add              // +
 	Sub              // -
 	Ident
 	Period // .

 	// not to be used
 	SingleBefore
 	// not to be used
 	BeforeAndInline // inline
 	InlineGeneral /* inline general */
 )
 `

 const tokens_out = `func _() {
 	// An "invalid array index" compiler error signifies that the constant values have changed.
 	// Re-run the stringer command to generate them again.
 	var x [1]struct{}
 	_ = x[And-0]
 	_ = x[Or-1]
 	_ = x[Add-2]
 	_ = x[Sub-3]
 	_ = x[Ident-4]
 	_ = x[Period-5]
 	_ = x[SingleBefore-6]
 	_ = x[BeforeAndInline-7]
 	_ = x[InlineGeneral-8]
 }

 const _Token_name = "&|+-Ident.SingleBeforeinlineinline general"

 var _Token_index = [...]uint8{0, 1, 2, 3, 4, 9, 10, 22, 28, 42}

 func (i Token) String() string {
 	if i < 0 || i >= Token(len(_Token_index)-1) {
 		return "Token(" + strconv.FormatInt(int64(i), 10) + ")"
 	}
 	return _Token_name[_Token_index[i]:_Token_index[i+1]]
 }
 `

 func TestGolden(t *testing.T) {
 	testenv.NeedsTool(t, "go")

 	dir, err := ioutil.TempDir("", "stringer")
 	if err != nil {
 		t.Error(err)
 	}
 	defer os.RemoveAll(dir)

 	for _, test := range golden {
 		g := Generator{
 			trimPrefix:  test.trimPrefix,
 			lineComment: test.lineComment,
 		}
 		input := "package test\n" + test.input
 		file := test.name + ".go"
 		absFile := filepath.Join(dir, file)
 		err := ioutil.WriteFile(absFile, []byte(input), 0644)
 		if err != nil {
 			t.Error(err)
 		}

 		g.parsePackage([]string{absFile}, nil)
 		// Extract the name and type of the constant from the first line.
 		tokens := strings.SplitN(test.input, " ", 3)
 		if len(tokens) != 3 {
 			t.Fatalf("%s: need type declaration on first line", test.name)
 		}
 		g.generate(tokens[1])
 		got := string(g.format())
 		if got != test.output {
 			t.Errorf("%s: got(%d)\n====\n%q====\nexpected(%d)\n====%q", test.name, len(got), got, len(test.output), test.output)
 		}
 	}
 }
	// Copyright 2014 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	// This file contains simple golden tests for various examples.
	// Besides validating the results when the implementation changes,
	// it provides a way to look at the generated code without having
	// to execute the print statements in one's head.

	package main

	import (
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"golang.org/x/tools/internal/testenv"
	)

	// Golden represents a test case.
	type Golden struct {
	name string
	trimPrefix string
	lineComment bool
	input string // input; the package clause is provided when running the test.
	output string // expected output.
	}

	var golden = []Golden{
	{"day", "", false, day_in, day_out},
	{"offset", "", false, offset_in, offset_out},
	{"gap", "", false, gap_in, gap_out},
	{"num", "", false, num_in, num_out},
	{"unum", "", false, unum_in, unum_out},
	{"unumpos", "", false, unumpos_in, unumpos_out},
	{"prime", "", false, prime_in, prime_out},
	{"prefix", "Type", false, prefix_in, prefix_out},
	{"tokens", "", true, tokens_in, tokens_out},
	}

	// Each example starts with "type XXX [u]int", with a single space separating them.

	// Simple test: enumeration of type int starting at 0.
	const day_in = `type Day int
	const (
	Monday Day = iota
	Tuesday
	Wednesday
	Thursday
	Friday
	Saturday
	Sunday
	)
	`

	const day_out = `func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[Monday-0]
	_ = x[Tuesday-1]
	_ = x[Wednesday-2]
	_ = x[Thursday-3]
	_ = x[Friday-4]
	_ = x[Saturday-5]
	_ = x[Sunday-6]
	}

	const _Day_name = "MondayTuesdayWednesdayThursdayFridaySaturdaySunday"

	var _Day_index = [...]uint8{0, 6, 13, 22, 30, 36, 44, 50}

	func (i Day) String() string {
	if i < 0 \|\| i >= Day(len(_Day_index)-1) {
	return "Day(" + strconv.FormatInt(int64(i), 10) + ")"
	}
	return _Day_name[_Day_index[i]:_Day_index[i+1]]
	}
	`

	// Enumeration with an offset.
	// Also includes a duplicate.
	const offset_in = `type Number int
	const (
	_ Number = iota
	One
	Two
	Three
	AnotherOne = One // Duplicate; note that AnotherOne doesn't appear below.
	)
	`

	const offset_out = `func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[One-1]
	_ = x[Two-2]
	_ = x[Three-3]
	}

	const _Number_name = "OneTwoThree"

	var _Number_index = [...]uint8{0, 3, 6, 11}

	func (i Number) String() string {
	i -= 1
	if i < 0 \|\| i >= Number(len(_Number_index)-1) {
	return "Number(" + strconv.FormatInt(int64(i+1), 10) + ")"
	}
	return _Number_name[_Number_index[i]:_Number_index[i+1]]
	}
	`

	// Gaps and an offset.
	const gap_in = `type Gap int
	const (
	Two Gap = 2
	Three Gap = 3
	Five Gap = 5
	Six Gap = 6
	Seven Gap = 7
	Eight Gap = 8
	Nine Gap = 9
	Eleven Gap = 11
	)
	`

	const gap_out = `func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[Two-2]
	_ = x[Three-3]
	_ = x[Five-5]
	_ = x[Six-6]
	_ = x[Seven-7]
	_ = x[Eight-8]
	_ = x[Nine-9]
	_ = x[Eleven-11]
	}

	const (
	_Gap_name_0 = "TwoThree"
	_Gap_name_1 = "FiveSixSevenEightNine"
	_Gap_name_2 = "Eleven"
	)

	var (
	_Gap_index_0 = [...]uint8{0, 3, 8}
	_Gap_index_1 = [...]uint8{0, 4, 7, 12, 17, 21}
	)

	func (i Gap) String() string {
	switch {
	case 2 <= i && i <= 3:
	i -= 2
	return _Gap_name_0[_Gap_index_0[i]:_Gap_index_0[i+1]]
	case 5 <= i && i <= 9:
	i -= 5
	return _Gap_name_1[_Gap_index_1[i]:_Gap_index_1[i+1]]
	case i == 11:
	return _Gap_name_2
	default:
	return "Gap(" + strconv.FormatInt(int64(i), 10) + ")"
	}
	}
	`

	// Signed integers spanning zero.
	const num_in = `type Num int
	const (
	m_2 Num = -2 + iota
	m_1
	m0
	m1
	m2
	)
	`

	const num_out = `func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[m_2 - -2]
	_ = x[m_1 - -1]
	_ = x[m0-0]
	_ = x[m1-1]
	_ = x[m2-2]
	}

	const _Num_name = "m_2m_1m0m1m2"

	var _Num_index = [...]uint8{0, 3, 6, 8, 10, 12}

	func (i Num) String() string {
	i -= -2
	if i < 0 \|\| i >= Num(len(_Num_index)-1) {
	return "Num(" + strconv.FormatInt(int64(i+-2), 10) + ")"
	}
	return _Num_name[_Num_index[i]:_Num_index[i+1]]
	}
	`

	// Unsigned integers spanning zero.
	const unum_in = `type Unum uint
	const (
	m_2 Unum = iota + 253
	m_1
	)

	const (
	m0 Unum = iota
	m1
	m2
	)
	`

	const unum_out = `func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[m_2-253]
	_ = x[m_1-254]
	_ = x[m0-0]
	_ = x[m1-1]
	_ = x[m2-2]
	}

	const (
	_Unum_name_0 = "m0m1m2"
	_Unum_name_1 = "m_2m_1"
	)

	var (
	_Unum_index_0 = [...]uint8{0, 2, 4, 6}
	_Unum_index_1 = [...]uint8{0, 3, 6}
	)

	func (i Unum) String() string {
	switch {
	case i <= 2:
	return _Unum_name_0[_Unum_index_0[i]:_Unum_index_0[i+1]]
	case 253 <= i && i <= 254:
	i -= 253
	return _Unum_name_1[_Unum_index_1[i]:_Unum_index_1[i+1]]
	default:
	return "Unum(" + strconv.FormatInt(int64(i), 10) + ")"
	}
	}
	`

	// Unsigned positive integers.
	const unumpos_in = `type Unumpos uint
	const (
	m253 Unumpos = iota + 253
	m254
	)

	const (
	m1 Unumpos = iota + 1
	m2
	m3
	)
	`

	const unumpos_out = `func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[m253-253]
	_ = x[m254-254]
	_ = x[m1-1]
	_ = x[m2-2]
	_ = x[m3-3]
	}

	const (
	_Unumpos_name_0 = "m1m2m3"
	_Unumpos_name_1 = "m253m254"
	)

	var (
	_Unumpos_index_0 = [...]uint8{0, 2, 4, 6}
	_Unumpos_index_1 = [...]uint8{0, 4, 8}
	)

	func (i Unumpos) String() string {
	switch {
	case 1 <= i && i <= 3:
	i -= 1
	return _Unumpos_name_0[_Unumpos_index_0[i]:_Unumpos_index_0[i+1]]
	case 253 <= i && i <= 254:
	i -= 253
	return _Unumpos_name_1[_Unumpos_index_1[i]:_Unumpos_index_1[i+1]]
	default:
	return "Unumpos(" + strconv.FormatInt(int64(i), 10) + ")"
	}
	}
	`

	// Enough gaps to trigger a map implementation of the method.
	// Also includes a duplicate to test that it doesn't cause problems
	const prime_in = `type Prime int
	const (
	p2 Prime = 2
	p3 Prime = 3
	p5 Prime = 5
	p7 Prime = 7
	p77 Prime = 7 // Duplicate; note that p77 doesn't appear below.
	p11 Prime = 11
	p13 Prime = 13
	p17 Prime = 17
	p19 Prime = 19
	p23 Prime = 23
	p29 Prime = 29
	p37 Prime = 31
	p41 Prime = 41
	p43 Prime = 43
	)
	`

	const prime_out = `func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[p2-2]
	_ = x[p3-3]
	_ = x[p5-5]
	_ = x[p7-7]
	_ = x[p77-7]
	_ = x[p11-11]
	_ = x[p13-13]
	_ = x[p17-17]
	_ = x[p19-19]
	_ = x[p23-23]
	_ = x[p29-29]
	_ = x[p37-31]
	_ = x[p41-41]
	_ = x[p43-43]
	}

	const _Prime_name = "p2p3p5p7p11p13p17p19p23p29p37p41p43"

	var _Prime_map = map[Prime]string{
	2: _Prime_name[0:2],
	3: _Prime_name[2:4],
	5: _Prime_name[4:6],
	7: _Prime_name[6:8],
	11: _Prime_name[8:11],
	13: _Prime_name[11:14],
	17: _Prime_name[14:17],
	19: _Prime_name[17:20],
	23: _Prime_name[20:23],
	29: _Prime_name[23:26],
	31: _Prime_name[26:29],
	41: _Prime_name[29:32],
	43: _Prime_name[32:35],
	}

	func (i Prime) String() string {
	if str, ok := _Prime_map[i]; ok {
	return str
	}
	return "Prime(" + strconv.FormatInt(int64(i), 10) + ")"
	}
	`

	const prefix_in = `type Type int
	const (
	TypeInt Type = iota
	TypeString
	TypeFloat
	TypeRune
	TypeByte
	TypeStruct
	TypeSlice
	)
	`

	const prefix_out = `func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[TypeInt-0]
	_ = x[TypeString-1]
	_ = x[TypeFloat-2]
	_ = x[TypeRune-3]
	_ = x[TypeByte-4]
	_ = x[TypeStruct-5]
	_ = x[TypeSlice-6]
	}

	const _Type_name = "IntStringFloatRuneByteStructSlice"

	var _Type_index = [...]uint8{0, 3, 9, 14, 18, 22, 28, 33}

	func (i Type) String() string {
	if i < 0 \|\| i >= Type(len(_Type_index)-1) {
	return "Type(" + strconv.FormatInt(int64(i), 10) + ")"
	}
	return _Type_name[_Type_index[i]:_Type_index[i+1]]
	}
	`

	const tokens_in = `type Token int
	const (
	And Token = iota // &
	Or // \|
	Add // +
	Sub // -
	Ident
	Period // .

	// not to be used
	SingleBefore
	// not to be used
	BeforeAndInline // inline
	InlineGeneral /* inline general */
	)
	`

	const tokens_out = `func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[And-0]
	_ = x[Or-1]
	_ = x[Add-2]
	_ = x[Sub-3]
	_ = x[Ident-4]
	_ = x[Period-5]
	_ = x[SingleBefore-6]
	_ = x[BeforeAndInline-7]
	_ = x[InlineGeneral-8]
	}

	const _Token_name = "&\|+-Ident.SingleBeforeinlineinline general"

	var _Token_index = [...]uint8{0, 1, 2, 3, 4, 9, 10, 22, 28, 42}

	func (i Token) String() string {
	if i < 0 \|\| i >= Token(len(_Token_index)-1) {
	return "Token(" + strconv.FormatInt(int64(i), 10) + ")"
	}
	return _Token_name[_Token_index[i]:_Token_index[i+1]]
	}
	`

	func TestGolden(t *testing.T) {
	testenv.NeedsTool(t, "go")

	dir, err := ioutil.TempDir("", "stringer")
	if err != nil {
	t.Error(err)
	}
	defer os.RemoveAll(dir)

	for _, test := range golden {
	g := Generator{
	trimPrefix: test.trimPrefix,
	lineComment: test.lineComment,
	}
	input := "package test\n" + test.input
	file := test.name + ".go"
	absFile := filepath.Join(dir, file)
	err := ioutil.WriteFile(absFile, []byte(input), 0644)
	if err != nil {
	t.Error(err)
	}

	g.parsePackage([]string{absFile}, nil)
	// Extract the name and type of the constant from the first line.
	tokens := strings.SplitN(test.input, " ", 3)
	if len(tokens) != 3 {
	t.Fatalf("%s: need type declaration on first line", test.name)
	}
	g.generate(tokens[1])
	got := string(g.format())
	if got != test.output {
	t.Errorf("%s: got(%d)\n====\n%q====\nexpected(%d)\n====%q", test.name, len(got), got, len(test.output), test.output)
	}
	}
	}