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      1 // Copyright 2011 The Go Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style
      3 // license that can be found in the LICENSE file.
      4 
      5 package template
      6 
      7 import (
      8 	"bytes"
      9 	"errors"
     10 	"flag"
     11 	"fmt"
     12 	"io/ioutil"
     13 	"reflect"
     14 	"strings"
     15 	"testing"
     16 )
     17 
     18 var debug = flag.Bool("debug", false, "show the errors produced by the tests")
     19 
     20 // T has lots of interesting pieces to use to test execution.
     21 type T struct {
     22 	// Basics
     23 	True        bool
     24 	I           int
     25 	U16         uint16
     26 	X           string
     27 	FloatZero   float64
     28 	ComplexZero complex128
     29 	// Nested structs.
     30 	U *U
     31 	// Struct with String method.
     32 	V0     V
     33 	V1, V2 *V
     34 	// Struct with Error method.
     35 	W0     W
     36 	W1, W2 *W
     37 	// Slices
     38 	SI      []int
     39 	SIEmpty []int
     40 	SB      []bool
     41 	// Maps
     42 	MSI      map[string]int
     43 	MSIone   map[string]int // one element, for deterministic output
     44 	MSIEmpty map[string]int
     45 	MXI      map[interface{}]int
     46 	MII      map[int]int
     47 	SMSI     []map[string]int
     48 	// Empty interfaces; used to see if we can dig inside one.
     49 	Empty0 interface{} // nil
     50 	Empty1 interface{}
     51 	Empty2 interface{}
     52 	Empty3 interface{}
     53 	Empty4 interface{}
     54 	// Non-empty interfaces.
     55 	NonEmptyInterface    I
     56 	NonEmptyInterfacePtS *I
     57 	// Stringer.
     58 	Str fmt.Stringer
     59 	Err error
     60 	// Pointers
     61 	PI  *int
     62 	PS  *string
     63 	PSI *[]int
     64 	NIL *int
     65 	// Function (not method)
     66 	BinaryFunc      func(string, string) string
     67 	VariadicFunc    func(...string) string
     68 	VariadicFuncInt func(int, ...string) string
     69 	NilOKFunc       func(*int) bool
     70 	ErrFunc         func() (string, error)
     71 	// Template to test evaluation of templates.
     72 	Tmpl *Template
     73 	// Unexported field; cannot be accessed by template.
     74 	unexported int
     75 }
     76 
     77 type S []string
     78 
     79 func (S) Method0() string {
     80 	return "M0"
     81 }
     82 
     83 type U struct {
     84 	V string
     85 }
     86 
     87 type V struct {
     88 	j int
     89 }
     90 
     91 func (v *V) String() string {
     92 	if v == nil {
     93 		return "nilV"
     94 	}
     95 	return fmt.Sprintf("<%d>", v.j)
     96 }
     97 
     98 type W struct {
     99 	k int
    100 }
    101 
    102 func (w *W) Error() string {
    103 	if w == nil {
    104 		return "nilW"
    105 	}
    106 	return fmt.Sprintf("[%d]", w.k)
    107 }
    108 
    109 var siVal = I(S{"a", "b"})
    110 
    111 var tVal = &T{
    112 	True:   true,
    113 	I:      17,
    114 	U16:    16,
    115 	X:      "x",
    116 	U:      &U{"v"},
    117 	V0:     V{6666},
    118 	V1:     &V{7777}, // leave V2 as nil
    119 	W0:     W{888},
    120 	W1:     &W{999}, // leave W2 as nil
    121 	SI:     []int{3, 4, 5},
    122 	SB:     []bool{true, false},
    123 	MSI:    map[string]int{"one": 1, "two": 2, "three": 3},
    124 	MSIone: map[string]int{"one": 1},
    125 	MXI:    map[interface{}]int{"one": 1},
    126 	MII:    map[int]int{1: 1},
    127 	SMSI: []map[string]int{
    128 		{"one": 1, "two": 2},
    129 		{"eleven": 11, "twelve": 12},
    130 	},
    131 	Empty1:               3,
    132 	Empty2:               "empty2",
    133 	Empty3:               []int{7, 8},
    134 	Empty4:               &U{"UinEmpty"},
    135 	NonEmptyInterface:    &T{X: "x"},
    136 	NonEmptyInterfacePtS: &siVal,
    137 	Str:                  bytes.NewBuffer([]byte("foozle")),
    138 	Err:                  errors.New("erroozle"),
    139 	PI:                   newInt(23),
    140 	PS:                   newString("a string"),
    141 	PSI:                  newIntSlice(21, 22, 23),
    142 	BinaryFunc:           func(a, b string) string { return fmt.Sprintf("[%s=%s]", a, b) },
    143 	VariadicFunc:         func(s ...string) string { return fmt.Sprint("<", strings.Join(s, "+"), ">") },
    144 	VariadicFuncInt:      func(a int, s ...string) string { return fmt.Sprint(a, "=<", strings.Join(s, "+"), ">") },
    145 	NilOKFunc:            func(s *int) bool { return s == nil },
    146 	ErrFunc:              func() (string, error) { return "bla", nil },
    147 	Tmpl:                 Must(New("x").Parse("test template")), // "x" is the value of .X
    148 }
    149 
    150 // A non-empty interface.
    151 type I interface {
    152 	Method0() string
    153 }
    154 
    155 var iVal I = tVal
    156 
    157 // Helpers for creation.
    158 func newInt(n int) *int {
    159 	return &n
    160 }
    161 
    162 func newString(s string) *string {
    163 	return &s
    164 }
    165 
    166 func newIntSlice(n ...int) *[]int {
    167 	p := new([]int)
    168 	*p = make([]int, len(n))
    169 	copy(*p, n)
    170 	return p
    171 }
    172 
    173 // Simple methods with and without arguments.
    174 func (t *T) Method0() string {
    175 	return "M0"
    176 }
    177 
    178 func (t *T) Method1(a int) int {
    179 	return a
    180 }
    181 
    182 func (t *T) Method2(a uint16, b string) string {
    183 	return fmt.Sprintf("Method2: %d %s", a, b)
    184 }
    185 
    186 func (t *T) Method3(v interface{}) string {
    187 	return fmt.Sprintf("Method3: %v", v)
    188 }
    189 
    190 func (t *T) Copy() *T {
    191 	n := new(T)
    192 	*n = *t
    193 	return n
    194 }
    195 
    196 func (t *T) MAdd(a int, b []int) []int {
    197 	v := make([]int, len(b))
    198 	for i, x := range b {
    199 		v[i] = x + a
    200 	}
    201 	return v
    202 }
    203 
    204 var myError = errors.New("my error")
    205 
    206 // MyError returns a value and an error according to its argument.
    207 func (t *T) MyError(error bool) (bool, error) {
    208 	if error {
    209 		return true, myError
    210 	}
    211 	return false, nil
    212 }
    213 
    214 // A few methods to test chaining.
    215 func (t *T) GetU() *U {
    216 	return t.U
    217 }
    218 
    219 func (u *U) TrueFalse(b bool) string {
    220 	if b {
    221 		return "true"
    222 	}
    223 	return ""
    224 }
    225 
    226 func typeOf(arg interface{}) string {
    227 	return fmt.Sprintf("%T", arg)
    228 }
    229 
    230 type execTest struct {
    231 	name   string
    232 	input  string
    233 	output string
    234 	data   interface{}
    235 	ok     bool
    236 }
    237 
    238 // bigInt and bigUint are hex string representing numbers either side
    239 // of the max int boundary.
    240 // We do it this way so the test doesn't depend on ints being 32 bits.
    241 var (
    242 	bigInt  = fmt.Sprintf("0x%x", int(1<<uint(reflect.TypeOf(0).Bits()-1)-1))
    243 	bigUint = fmt.Sprintf("0x%x", uint(1<<uint(reflect.TypeOf(0).Bits()-1)))
    244 )
    245 
    246 var execTests = []execTest{
    247 	// Trivial cases.
    248 	{"empty", "", "", nil, true},
    249 	{"text", "some text", "some text", nil, true},
    250 	{"nil action", "{{nil}}", "", nil, false},
    251 
    252 	// Ideal constants.
    253 	{"ideal int", "{{typeOf 3}}", "int", 0, true},
    254 	{"ideal float", "{{typeOf 1.0}}", "float64", 0, true},
    255 	{"ideal exp float", "{{typeOf 1e1}}", "float64", 0, true},
    256 	{"ideal complex", "{{typeOf 1i}}", "complex128", 0, true},
    257 	{"ideal int", "{{typeOf " + bigInt + "}}", "int", 0, true},
    258 	{"ideal too big", "{{typeOf " + bigUint + "}}", "", 0, false},
    259 	{"ideal nil without type", "{{nil}}", "", 0, false},
    260 
    261 	// Fields of structs.
    262 	{".X", "-{{.X}}-", "-x-", tVal, true},
    263 	{".U.V", "-{{.U.V}}-", "-v-", tVal, true},
    264 	{".unexported", "{{.unexported}}", "", tVal, false},
    265 
    266 	// Fields on maps.
    267 	{"map .one", "{{.MSI.one}}", "1", tVal, true},
    268 	{"map .two", "{{.MSI.two}}", "2", tVal, true},
    269 	{"map .NO", "{{.MSI.NO}}", "<no value>", tVal, true},
    270 	{"map .one interface", "{{.MXI.one}}", "1", tVal, true},
    271 	{"map .WRONG args", "{{.MSI.one 1}}", "", tVal, false},
    272 	{"map .WRONG type", "{{.MII.one}}", "", tVal, false},
    273 
    274 	// Dots of all kinds to test basic evaluation.
    275 	{"dot int", "<{{.}}>", "<13>", 13, true},
    276 	{"dot uint", "<{{.}}>", "<14>", uint(14), true},
    277 	{"dot float", "<{{.}}>", "<15.1>", 15.1, true},
    278 	{"dot bool", "<{{.}}>", "<true>", true, true},
    279 	{"dot complex", "<{{.}}>", "<(16.2-17i)>", 16.2 - 17i, true},
    280 	{"dot string", "<{{.}}>", "<hello>", "hello", true},
    281 	{"dot slice", "<{{.}}>", "<[-1 -2 -3]>", []int{-1, -2, -3}, true},
    282 	{"dot map", "<{{.}}>", "<map[two:22]>", map[string]int{"two": 22}, true},
    283 	{"dot struct", "<{{.}}>", "<{7 seven}>", struct {
    284 		a int
    285 		b string
    286 	}{7, "seven"}, true},
    287 
    288 	// Variables.
    289 	{"$ int", "{{$}}", "123", 123, true},
    290 	{"$.I", "{{$.I}}", "17", tVal, true},
    291 	{"$.U.V", "{{$.U.V}}", "v", tVal, true},
    292 	{"declare in action", "{{$x := $.U.V}}{{$x}}", "v", tVal, true},
    293 
    294 	// Type with String method.
    295 	{"V{6666}.String()", "-{{.V0}}-", "-<6666>-", tVal, true},
    296 	{"&V{7777}.String()", "-{{.V1}}-", "-<7777>-", tVal, true},
    297 	{"(*V)(nil).String()", "-{{.V2}}-", "-nilV-", tVal, true},
    298 
    299 	// Type with Error method.
    300 	{"W{888}.Error()", "-{{.W0}}-", "-[888]-", tVal, true},
    301 	{"&W{999}.Error()", "-{{.W1}}-", "-[999]-", tVal, true},
    302 	{"(*W)(nil).Error()", "-{{.W2}}-", "-nilW-", tVal, true},
    303 
    304 	// Pointers.
    305 	{"*int", "{{.PI}}", "23", tVal, true},
    306 	{"*string", "{{.PS}}", "a string", tVal, true},
    307 	{"*[]int", "{{.PSI}}", "[21 22 23]", tVal, true},
    308 	{"*[]int[1]", "{{index .PSI 1}}", "22", tVal, true},
    309 	{"NIL", "{{.NIL}}", "<nil>", tVal, true},
    310 
    311 	// Empty interfaces holding values.
    312 	{"empty nil", "{{.Empty0}}", "<no value>", tVal, true},
    313 	{"empty with int", "{{.Empty1}}", "3", tVal, true},
    314 	{"empty with string", "{{.Empty2}}", "empty2", tVal, true},
    315 	{"empty with slice", "{{.Empty3}}", "[7 8]", tVal, true},
    316 	{"empty with struct", "{{.Empty4}}", "{UinEmpty}", tVal, true},
    317 	{"empty with struct, field", "{{.Empty4.V}}", "UinEmpty", tVal, true},
    318 
    319 	// Method calls.
    320 	{".Method0", "-{{.Method0}}-", "-M0-", tVal, true},
    321 	{".Method1(1234)", "-{{.Method1 1234}}-", "-1234-", tVal, true},
    322 	{".Method1(.I)", "-{{.Method1 .I}}-", "-17-", tVal, true},
    323 	{".Method2(3, .X)", "-{{.Method2 3 .X}}-", "-Method2: 3 x-", tVal, true},
    324 	{".Method2(.U16, `str`)", "-{{.Method2 .U16 `str`}}-", "-Method2: 16 str-", tVal, true},
    325 	{".Method2(.U16, $x)", "{{if $x := .X}}-{{.Method2 .U16 $x}}{{end}}-", "-Method2: 16 x-", tVal, true},
    326 	{".Method3(nil constant)", "-{{.Method3 nil}}-", "-Method3: <nil>-", tVal, true},
    327 	{".Method3(nil value)", "-{{.Method3 .MXI.unset}}-", "-Method3: <nil>-", tVal, true},
    328 	{"method on var", "{{if $x := .}}-{{$x.Method2 .U16 $x.X}}{{end}}-", "-Method2: 16 x-", tVal, true},
    329 	{"method on chained var",
    330 		"{{range .MSIone}}{{if $.U.TrueFalse $.True}}{{$.U.TrueFalse $.True}}{{else}}WRONG{{end}}{{end}}",
    331 		"true", tVal, true},
    332 	{"chained method",
    333 		"{{range .MSIone}}{{if $.GetU.TrueFalse $.True}}{{$.U.TrueFalse $.True}}{{else}}WRONG{{end}}{{end}}",
    334 		"true", tVal, true},
    335 	{"chained method on variable",
    336 		"{{with $x := .}}{{with .SI}}{{$.GetU.TrueFalse $.True}}{{end}}{{end}}",
    337 		"true", tVal, true},
    338 	{".NilOKFunc not nil", "{{call .NilOKFunc .PI}}", "false", tVal, true},
    339 	{".NilOKFunc nil", "{{call .NilOKFunc nil}}", "true", tVal, true},
    340 
    341 	// Function call builtin.
    342 	{".BinaryFunc", "{{call .BinaryFunc `1` `2`}}", "[1=2]", tVal, true},
    343 	{".VariadicFunc0", "{{call .VariadicFunc}}", "<>", tVal, true},
    344 	{".VariadicFunc2", "{{call .VariadicFunc `he` `llo`}}", "<he+llo>", tVal, true},
    345 	{".VariadicFuncInt", "{{call .VariadicFuncInt 33 `he` `llo`}}", "33=<he+llo>", tVal, true},
    346 	{"if .BinaryFunc call", "{{ if .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{end}}", "[1=2]", tVal, true},
    347 	{"if not .BinaryFunc call", "{{ if not .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{else}}No{{end}}", "No", tVal, true},
    348 	{"Interface Call", `{{stringer .S}}`, "foozle", map[string]interface{}{"S": bytes.NewBufferString("foozle")}, true},
    349 	{".ErrFunc", "{{call .ErrFunc}}", "bla", tVal, true},
    350 	{"call nil", "{{call nil}}", "", tVal, false},
    351 
    352 	// Erroneous function calls (check args).
    353 	{".BinaryFuncTooFew", "{{call .BinaryFunc `1`}}", "", tVal, false},
    354 	{".BinaryFuncTooMany", "{{call .BinaryFunc `1` `2` `3`}}", "", tVal, false},
    355 	{".BinaryFuncBad0", "{{call .BinaryFunc 1 3}}", "", tVal, false},
    356 	{".BinaryFuncBad1", "{{call .BinaryFunc `1` 3}}", "", tVal, false},
    357 	{".VariadicFuncBad0", "{{call .VariadicFunc 3}}", "", tVal, false},
    358 	{".VariadicFuncIntBad0", "{{call .VariadicFuncInt}}", "", tVal, false},
    359 	{".VariadicFuncIntBad`", "{{call .VariadicFuncInt `x`}}", "", tVal, false},
    360 	{".VariadicFuncNilBad", "{{call .VariadicFunc nil}}", "", tVal, false},
    361 
    362 	// Pipelines.
    363 	{"pipeline", "-{{.Method0 | .Method2 .U16}}-", "-Method2: 16 M0-", tVal, true},
    364 	{"pipeline func", "-{{call .VariadicFunc `llo` | call .VariadicFunc `he` }}-", "-<he+<llo>>-", tVal, true},
    365 
    366 	// Parenthesized expressions
    367 	{"parens in pipeline", "{{printf `%d %d %d` (1) (2 | add 3) (add 4 (add 5 6))}}", "1 5 15", tVal, true},
    368 
    369 	// Parenthesized expressions with field accesses
    370 	{"parens: $ in paren", "{{($).X}}", "x", tVal, true},
    371 	{"parens: $.GetU in paren", "{{($.GetU).V}}", "v", tVal, true},
    372 	{"parens: $ in paren in pipe", "{{($ | echo).X}}", "x", tVal, true},
    373 	{"parens: spaces and args", `{{(makemap "up" "down" "left" "right").left}}`, "right", tVal, true},
    374 
    375 	// If.
    376 	{"if true", "{{if true}}TRUE{{end}}", "TRUE", tVal, true},
    377 	{"if false", "{{if false}}TRUE{{else}}FALSE{{end}}", "FALSE", tVal, true},
    378 	{"if nil", "{{if nil}}TRUE{{end}}", "", tVal, false},
    379 	{"if 1", "{{if 1}}NON-ZERO{{else}}ZERO{{end}}", "NON-ZERO", tVal, true},
    380 	{"if 0", "{{if 0}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
    381 	{"if 1.5", "{{if 1.5}}NON-ZERO{{else}}ZERO{{end}}", "NON-ZERO", tVal, true},
    382 	{"if 0.0", "{{if .FloatZero}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
    383 	{"if 1.5i", "{{if 1.5i}}NON-ZERO{{else}}ZERO{{end}}", "NON-ZERO", tVal, true},
    384 	{"if 0.0i", "{{if .ComplexZero}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
    385 	{"if emptystring", "{{if ``}}NON-EMPTY{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
    386 	{"if string", "{{if `notempty`}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
    387 	{"if emptyslice", "{{if .SIEmpty}}NON-EMPTY{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
    388 	{"if slice", "{{if .SI}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
    389 	{"if emptymap", "{{if .MSIEmpty}}NON-EMPTY{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
    390 	{"if map", "{{if .MSI}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
    391 	{"if map unset", "{{if .MXI.none}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
    392 	{"if map not unset", "{{if not .MXI.none}}ZERO{{else}}NON-ZERO{{end}}", "ZERO", tVal, true},
    393 	{"if $x with $y int", "{{if $x := true}}{{with $y := .I}}{{$x}},{{$y}}{{end}}{{end}}", "true,17", tVal, true},
    394 	{"if $x with $x int", "{{if $x := true}}{{with $x := .I}}{{$x}},{{end}}{{$x}}{{end}}", "17,true", tVal, true},
    395 	{"if else if", "{{if false}}FALSE{{else if true}}TRUE{{end}}", "TRUE", tVal, true},
    396 	{"if else chain", "{{if eq 1 3}}1{{else if eq 2 3}}2{{else if eq 3 3}}3{{end}}", "3", tVal, true},
    397 
    398 	// Print etc.
    399 	{"print", `{{print "hello, print"}}`, "hello, print", tVal, true},
    400 	{"print 123", `{{print 1 2 3}}`, "1 2 3", tVal, true},
    401 	{"print nil", `{{print nil}}`, "<nil>", tVal, true},
    402 	{"println", `{{println 1 2 3}}`, "1 2 3\n", tVal, true},
    403 	{"printf int", `{{printf "%04x" 127}}`, "007f", tVal, true},
    404 	{"printf float", `{{printf "%g" 3.5}}`, "3.5", tVal, true},
    405 	{"printf complex", `{{printf "%g" 1+7i}}`, "(1+7i)", tVal, true},
    406 	{"printf string", `{{printf "%s" "hello"}}`, "hello", tVal, true},
    407 	{"printf function", `{{printf "%#q" zeroArgs}}`, "`zeroArgs`", tVal, true},
    408 	{"printf field", `{{printf "%s" .U.V}}`, "v", tVal, true},
    409 	{"printf method", `{{printf "%s" .Method0}}`, "M0", tVal, true},
    410 	{"printf dot", `{{with .I}}{{printf "%d" .}}{{end}}`, "17", tVal, true},
    411 	{"printf var", `{{with $x := .I}}{{printf "%d" $x}}{{end}}`, "17", tVal, true},
    412 	{"printf lots", `{{printf "%d %s %g %s" 127 "hello" 7-3i .Method0}}`, "127 hello (7-3i) M0", tVal, true},
    413 
    414 	// HTML.
    415 	{"html", `{{html "<script>alert(\"XSS\");</script>"}}`,
    416 		"&lt;script&gt;alert(&#34;XSS&#34;);&lt;/script&gt;", nil, true},
    417 	{"html pipeline", `{{printf "<script>alert(\"XSS\");</script>" | html}}`,
    418 		"&lt;script&gt;alert(&#34;XSS&#34;);&lt;/script&gt;", nil, true},
    419 	{"html", `{{html .PS}}`, "a string", tVal, true},
    420 
    421 	// JavaScript.
    422 	{"js", `{{js .}}`, `It\'d be nice.`, `It'd be nice.`, true},
    423 
    424 	// URL query.
    425 	{"urlquery", `{{"http://www.example.org/"|urlquery}}`, "http%3A%2F%2Fwww.example.org%2F", nil, true},
    426 
    427 	// Booleans
    428 	{"not", "{{not true}} {{not false}}", "false true", nil, true},
    429 	{"and", "{{and false 0}} {{and 1 0}} {{and 0 true}} {{and 1 1}}", "false 0 0 1", nil, true},
    430 	{"or", "{{or 0 0}} {{or 1 0}} {{or 0 true}} {{or 1 1}}", "0 1 true 1", nil, true},
    431 	{"boolean if", "{{if and true 1 `hi`}}TRUE{{else}}FALSE{{end}}", "TRUE", tVal, true},
    432 	{"boolean if not", "{{if and true 1 `hi` | not}}TRUE{{else}}FALSE{{end}}", "FALSE", nil, true},
    433 
    434 	// Indexing.
    435 	{"slice[0]", "{{index .SI 0}}", "3", tVal, true},
    436 	{"slice[1]", "{{index .SI 1}}", "4", tVal, true},
    437 	{"slice[HUGE]", "{{index .SI 10}}", "", tVal, false},
    438 	{"slice[WRONG]", "{{index .SI `hello`}}", "", tVal, false},
    439 	{"slice[nil]", "{{index .SI nil}}", "", tVal, false},
    440 	{"map[one]", "{{index .MSI `one`}}", "1", tVal, true},
    441 	{"map[two]", "{{index .MSI `two`}}", "2", tVal, true},
    442 	{"map[NO]", "{{index .MSI `XXX`}}", "0", tVal, true},
    443 	{"map[nil]", "{{index .MSI nil}}", "", tVal, false},
    444 	{"map[``]", "{{index .MSI ``}}", "0", tVal, true},
    445 	{"map[WRONG]", "{{index .MSI 10}}", "", tVal, false},
    446 	{"double index", "{{index .SMSI 1 `eleven`}}", "11", tVal, true},
    447 	{"nil[1]", "{{index nil 1}}", "", tVal, false},
    448 
    449 	// Len.
    450 	{"slice", "{{len .SI}}", "3", tVal, true},
    451 	{"map", "{{len .MSI }}", "3", tVal, true},
    452 	{"len of int", "{{len 3}}", "", tVal, false},
    453 	{"len of nothing", "{{len .Empty0}}", "", tVal, false},
    454 
    455 	// With.
    456 	{"with true", "{{with true}}{{.}}{{end}}", "true", tVal, true},
    457 	{"with false", "{{with false}}{{.}}{{else}}FALSE{{end}}", "FALSE", tVal, true},
    458 	{"with 1", "{{with 1}}{{.}}{{else}}ZERO{{end}}", "1", tVal, true},
    459 	{"with 0", "{{with 0}}{{.}}{{else}}ZERO{{end}}", "ZERO", tVal, true},
    460 	{"with 1.5", "{{with 1.5}}{{.}}{{else}}ZERO{{end}}", "1.5", tVal, true},
    461 	{"with 0.0", "{{with .FloatZero}}{{.}}{{else}}ZERO{{end}}", "ZERO", tVal, true},
    462 	{"with 1.5i", "{{with 1.5i}}{{.}}{{else}}ZERO{{end}}", "(0+1.5i)", tVal, true},
    463 	{"with 0.0i", "{{with .ComplexZero}}{{.}}{{else}}ZERO{{end}}", "ZERO", tVal, true},
    464 	{"with emptystring", "{{with ``}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
    465 	{"with string", "{{with `notempty`}}{{.}}{{else}}EMPTY{{end}}", "notempty", tVal, true},
    466 	{"with emptyslice", "{{with .SIEmpty}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
    467 	{"with slice", "{{with .SI}}{{.}}{{else}}EMPTY{{end}}", "[3 4 5]", tVal, true},
    468 	{"with emptymap", "{{with .MSIEmpty}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
    469 	{"with map", "{{with .MSIone}}{{.}}{{else}}EMPTY{{end}}", "map[one:1]", tVal, true},
    470 	{"with empty interface, struct field", "{{with .Empty4}}{{.V}}{{end}}", "UinEmpty", tVal, true},
    471 	{"with $x int", "{{with $x := .I}}{{$x}}{{end}}", "17", tVal, true},
    472 	{"with $x struct.U.V", "{{with $x := $}}{{$x.U.V}}{{end}}", "v", tVal, true},
    473 	{"with variable and action", "{{with $x := $}}{{$y := $.U.V}}{{$y}}{{end}}", "v", tVal, true},
    474 
    475 	// Range.
    476 	{"range []int", "{{range .SI}}-{{.}}-{{end}}", "-3--4--5-", tVal, true},
    477 	{"range empty no else", "{{range .SIEmpty}}-{{.}}-{{end}}", "", tVal, true},
    478 	{"range []int else", "{{range .SI}}-{{.}}-{{else}}EMPTY{{end}}", "-3--4--5-", tVal, true},
    479 	{"range empty else", "{{range .SIEmpty}}-{{.}}-{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
    480 	{"range []bool", "{{range .SB}}-{{.}}-{{end}}", "-true--false-", tVal, true},
    481 	{"range []int method", "{{range .SI | .MAdd .I}}-{{.}}-{{end}}", "-20--21--22-", tVal, true},
    482 	{"range map", "{{range .MSI}}-{{.}}-{{end}}", "-1--3--2-", tVal, true},
    483 	{"range empty map no else", "{{range .MSIEmpty}}-{{.}}-{{end}}", "", tVal, true},
    484 	{"range map else", "{{range .MSI}}-{{.}}-{{else}}EMPTY{{end}}", "-1--3--2-", tVal, true},
    485 	{"range empty map else", "{{range .MSIEmpty}}-{{.}}-{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
    486 	{"range empty interface", "{{range .Empty3}}-{{.}}-{{else}}EMPTY{{end}}", "-7--8-", tVal, true},
    487 	{"range empty nil", "{{range .Empty0}}-{{.}}-{{end}}", "", tVal, true},
    488 	{"range $x SI", "{{range $x := .SI}}<{{$x}}>{{end}}", "<3><4><5>", tVal, true},
    489 	{"range $x $y SI", "{{range $x, $y := .SI}}<{{$x}}={{$y}}>{{end}}", "<0=3><1=4><2=5>", tVal, true},
    490 	{"range $x MSIone", "{{range $x := .MSIone}}<{{$x}}>{{end}}", "<1>", tVal, true},
    491 	{"range $x $y MSIone", "{{range $x, $y := .MSIone}}<{{$x}}={{$y}}>{{end}}", "<one=1>", tVal, true},
    492 	{"range $x PSI", "{{range $x := .PSI}}<{{$x}}>{{end}}", "<21><22><23>", tVal, true},
    493 	{"declare in range", "{{range $x := .PSI}}<{{$foo:=$x}}{{$x}}>{{end}}", "<21><22><23>", tVal, true},
    494 	{"range count", `{{range $i, $x := count 5}}[{{$i}}]{{$x}}{{end}}`, "[0]a[1]b[2]c[3]d[4]e", tVal, true},
    495 	{"range nil count", `{{range $i, $x := count 0}}{{else}}empty{{end}}`, "empty", tVal, true},
    496 
    497 	// Cute examples.
    498 	{"or as if true", `{{or .SI "slice is empty"}}`, "[3 4 5]", tVal, true},
    499 	{"or as if false", `{{or .SIEmpty "slice is empty"}}`, "slice is empty", tVal, true},
    500 
    501 	// Error handling.
    502 	{"error method, error", "{{.MyError true}}", "", tVal, false},
    503 	{"error method, no error", "{{.MyError false}}", "false", tVal, true},
    504 
    505 	// Fixed bugs.
    506 	// Must separate dot and receiver; otherwise args are evaluated with dot set to variable.
    507 	{"bug0", "{{range .MSIone}}{{if $.Method1 .}}X{{end}}{{end}}", "X", tVal, true},
    508 	// Do not loop endlessly in indirect for non-empty interfaces.
    509 	// The bug appears with *interface only; looped forever.
    510 	{"bug1", "{{.Method0}}", "M0", &iVal, true},
    511 	// Was taking address of interface field, so method set was empty.
    512 	{"bug2", "{{$.NonEmptyInterface.Method0}}", "M0", tVal, true},
    513 	// Struct values were not legal in with - mere oversight.
    514 	{"bug3", "{{with $}}{{.Method0}}{{end}}", "M0", tVal, true},
    515 	// Nil interface values in if.
    516 	{"bug4", "{{if .Empty0}}non-nil{{else}}nil{{end}}", "nil", tVal, true},
    517 	// Stringer.
    518 	{"bug5", "{{.Str}}", "foozle", tVal, true},
    519 	{"bug5a", "{{.Err}}", "erroozle", tVal, true},
    520 	// Args need to be indirected and dereferenced sometimes.
    521 	{"bug6a", "{{vfunc .V0 .V1}}", "vfunc", tVal, true},
    522 	{"bug6b", "{{vfunc .V0 .V0}}", "vfunc", tVal, true},
    523 	{"bug6c", "{{vfunc .V1 .V0}}", "vfunc", tVal, true},
    524 	{"bug6d", "{{vfunc .V1 .V1}}", "vfunc", tVal, true},
    525 	// Legal parse but illegal execution: non-function should have no arguments.
    526 	{"bug7a", "{{3 2}}", "", tVal, false},
    527 	{"bug7b", "{{$x := 1}}{{$x 2}}", "", tVal, false},
    528 	{"bug7c", "{{$x := 1}}{{3 | $x}}", "", tVal, false},
    529 	// Pipelined arg was not being type-checked.
    530 	{"bug8a", "{{3|oneArg}}", "", tVal, false},
    531 	{"bug8b", "{{4|dddArg 3}}", "", tVal, false},
    532 	// A bug was introduced that broke map lookups for lower-case names.
    533 	{"bug9", "{{.cause}}", "neglect", map[string]string{"cause": "neglect"}, true},
    534 	// Field chain starting with function did not work.
    535 	{"bug10", "{{mapOfThree.three}}-{{(mapOfThree).three}}", "3-3", 0, true},
    536 	// Dereferencing nil pointer while evaluating function arguments should not panic. Issue 7333.
    537 	{"bug11", "{{valueString .PS}}", "", T{}, false},
    538 	// 0xef gave constant type float64. Issue 8622.
    539 	{"bug12xe", "{{printf `%T` 0xef}}", "int", T{}, true},
    540 	{"bug12xE", "{{printf `%T` 0xEE}}", "int", T{}, true},
    541 	{"bug12Xe", "{{printf `%T` 0Xef}}", "int", T{}, true},
    542 	{"bug12XE", "{{printf `%T` 0XEE}}", "int", T{}, true},
    543 	// Chained nodes did not work as arguments. Issue 8473.
    544 	{"bug13", "{{print (.Copy).I}}", "17", tVal, true},
    545 	// Didn't protect against nil or literal values in field chains.
    546 	{"bug14a", "{{(nil).True}}", "", tVal, false},
    547 	{"bug14b", "{{$x := nil}}{{$x.anything}}", "", tVal, false},
    548 	{"bug14c", `{{$x := (1.0)}}{{$y := ("hello")}}{{$x.anything}}{{$y.true}}`, "", tVal, false},
    549 	// Didn't call validateType on function results. Issue 10800.
    550 	{"bug15", "{{valueString returnInt}}", "", tVal, false},
    551 	// Variadic function corner cases. Issue 10946.
    552 	{"bug16a", "{{true|printf}}", "", tVal, false},
    553 	{"bug16b", "{{1|printf}}", "", tVal, false},
    554 	{"bug16c", "{{1.1|printf}}", "", tVal, false},
    555 	{"bug16d", "{{'x'|printf}}", "", tVal, false},
    556 	{"bug16e", "{{0i|printf}}", "", tVal, false},
    557 	{"bug16f", "{{true|twoArgs \"xxx\"}}", "", tVal, false},
    558 	{"bug16g", "{{\"aaa\" |twoArgs \"bbb\"}}", "twoArgs=bbbaaa", tVal, true},
    559 	{"bug16h", "{{1|oneArg}}", "", tVal, false},
    560 	{"bug16i", "{{\"aaa\"|oneArg}}", "oneArg=aaa", tVal, true},
    561 	{"bug16j", "{{1+2i|printf \"%v\"}}", "(1+2i)", tVal, true},
    562 	{"bug16k", "{{\"aaa\"|printf }}", "aaa", tVal, true},
    563 	{"bug17a", "{{.NonEmptyInterface.X}}", "x", tVal, true},
    564 	{"bug17b", "-{{.NonEmptyInterface.Method1 1234}}-", "-1234-", tVal, true},
    565 	{"bug17c", "{{len .NonEmptyInterfacePtS}}", "2", tVal, true},
    566 	{"bug17d", "{{index .NonEmptyInterfacePtS 0}}", "a", tVal, true},
    567 	{"bug17e", "{{range .NonEmptyInterfacePtS}}-{{.}}-{{end}}", "-a--b-", tVal, true},
    568 }
    569 
    570 func zeroArgs() string {
    571 	return "zeroArgs"
    572 }
    573 
    574 func oneArg(a string) string {
    575 	return "oneArg=" + a
    576 }
    577 
    578 func twoArgs(a, b string) string {
    579 	return "twoArgs=" + a + b
    580 }
    581 
    582 func dddArg(a int, b ...string) string {
    583 	return fmt.Sprintln(a, b)
    584 }
    585 
    586 // count returns a channel that will deliver n sequential 1-letter strings starting at "a"
    587 func count(n int) chan string {
    588 	if n == 0 {
    589 		return nil
    590 	}
    591 	c := make(chan string)
    592 	go func() {
    593 		for i := 0; i < n; i++ {
    594 			c <- "abcdefghijklmnop"[i : i+1]
    595 		}
    596 		close(c)
    597 	}()
    598 	return c
    599 }
    600 
    601 // vfunc takes a *V and a V
    602 func vfunc(V, *V) string {
    603 	return "vfunc"
    604 }
    605 
    606 // valueString takes a string, not a pointer.
    607 func valueString(v string) string {
    608 	return "value is ignored"
    609 }
    610 
    611 // returnInt returns an int
    612 func returnInt() int {
    613 	return 7
    614 }
    615 
    616 func add(args ...int) int {
    617 	sum := 0
    618 	for _, x := range args {
    619 		sum += x
    620 	}
    621 	return sum
    622 }
    623 
    624 func echo(arg interface{}) interface{} {
    625 	return arg
    626 }
    627 
    628 func makemap(arg ...string) map[string]string {
    629 	if len(arg)%2 != 0 {
    630 		panic("bad makemap")
    631 	}
    632 	m := make(map[string]string)
    633 	for i := 0; i < len(arg); i += 2 {
    634 		m[arg[i]] = arg[i+1]
    635 	}
    636 	return m
    637 }
    638 
    639 func stringer(s fmt.Stringer) string {
    640 	return s.String()
    641 }
    642 
    643 func mapOfThree() interface{} {
    644 	return map[string]int{"three": 3}
    645 }
    646 
    647 func testExecute(execTests []execTest, template *Template, t *testing.T) {
    648 	b := new(bytes.Buffer)
    649 	funcs := FuncMap{
    650 		"add":         add,
    651 		"count":       count,
    652 		"dddArg":      dddArg,
    653 		"echo":        echo,
    654 		"makemap":     makemap,
    655 		"mapOfThree":  mapOfThree,
    656 		"oneArg":      oneArg,
    657 		"returnInt":   returnInt,
    658 		"stringer":    stringer,
    659 		"twoArgs":     twoArgs,
    660 		"typeOf":      typeOf,
    661 		"valueString": valueString,
    662 		"vfunc":       vfunc,
    663 		"zeroArgs":    zeroArgs,
    664 	}
    665 	for _, test := range execTests {
    666 		var tmpl *Template
    667 		var err error
    668 		if template == nil {
    669 			tmpl, err = New(test.name).Funcs(funcs).Parse(test.input)
    670 		} else {
    671 			tmpl, err = template.New(test.name).Funcs(funcs).Parse(test.input)
    672 		}
    673 		if err != nil {
    674 			t.Errorf("%s: parse error: %s", test.name, err)
    675 			continue
    676 		}
    677 		b.Reset()
    678 		err = tmpl.Execute(b, test.data)
    679 		switch {
    680 		case !test.ok && err == nil:
    681 			t.Errorf("%s: expected error; got none", test.name)
    682 			continue
    683 		case test.ok && err != nil:
    684 			t.Errorf("%s: unexpected execute error: %s", test.name, err)
    685 			continue
    686 		case !test.ok && err != nil:
    687 			// expected error, got one
    688 			if *debug {
    689 				fmt.Printf("%s: %s\n\t%s\n", test.name, test.input, err)
    690 			}
    691 		}
    692 		result := b.String()
    693 		if result != test.output {
    694 			t.Errorf("%s: expected\n\t%q\ngot\n\t%q", test.name, test.output, result)
    695 		}
    696 	}
    697 }
    698 
    699 func TestExecute(t *testing.T) {
    700 	testExecute(execTests, nil, t)
    701 }
    702 
    703 var delimPairs = []string{
    704 	"", "", // default
    705 	"{{", "}}", // same as default
    706 	"<<", ">>", // distinct
    707 	"|", "|", // same
    708 	"()", "()", // peculiar
    709 }
    710 
    711 func TestDelims(t *testing.T) {
    712 	const hello = "Hello, world"
    713 	var value = struct{ Str string }{hello}
    714 	for i := 0; i < len(delimPairs); i += 2 {
    715 		text := ".Str"
    716 		left := delimPairs[i+0]
    717 		trueLeft := left
    718 		right := delimPairs[i+1]
    719 		trueRight := right
    720 		if left == "" { // default case
    721 			trueLeft = "{{"
    722 		}
    723 		if right == "" { // default case
    724 			trueRight = "}}"
    725 		}
    726 		text = trueLeft + text + trueRight
    727 		// Now add a comment
    728 		text += trueLeft + "/*comment*/" + trueRight
    729 		// Now add  an action containing a string.
    730 		text += trueLeft + `"` + trueLeft + `"` + trueRight
    731 		// At this point text looks like `{{.Str}}{{/*comment*/}}{{"{{"}}`.
    732 		tmpl, err := New("delims").Delims(left, right).Parse(text)
    733 		if err != nil {
    734 			t.Fatalf("delim %q text %q parse err %s", left, text, err)
    735 		}
    736 		var b = new(bytes.Buffer)
    737 		err = tmpl.Execute(b, value)
    738 		if err != nil {
    739 			t.Fatalf("delim %q exec err %s", left, err)
    740 		}
    741 		if b.String() != hello+trueLeft {
    742 			t.Errorf("expected %q got %q", hello+trueLeft, b.String())
    743 		}
    744 	}
    745 }
    746 
    747 // Check that an error from a method flows back to the top.
    748 func TestExecuteError(t *testing.T) {
    749 	b := new(bytes.Buffer)
    750 	tmpl := New("error")
    751 	_, err := tmpl.Parse("{{.MyError true}}")
    752 	if err != nil {
    753 		t.Fatalf("parse error: %s", err)
    754 	}
    755 	err = tmpl.Execute(b, tVal)
    756 	if err == nil {
    757 		t.Errorf("expected error; got none")
    758 	} else if !strings.Contains(err.Error(), myError.Error()) {
    759 		if *debug {
    760 			fmt.Printf("test execute error: %s\n", err)
    761 		}
    762 		t.Errorf("expected myError; got %s", err)
    763 	}
    764 }
    765 
    766 const execErrorText = `line 1
    767 line 2
    768 line 3
    769 {{template "one" .}}
    770 {{define "one"}}{{template "two" .}}{{end}}
    771 {{define "two"}}{{template "three" .}}{{end}}
    772 {{define "three"}}{{index "hi" $}}{{end}}`
    773 
    774 // Check that an error from a nested template contains all the relevant information.
    775 func TestExecError(t *testing.T) {
    776 	tmpl, err := New("top").Parse(execErrorText)
    777 	if err != nil {
    778 		t.Fatal("parse error:", err)
    779 	}
    780 	var b bytes.Buffer
    781 	err = tmpl.Execute(&b, 5) // 5 is out of range indexing "hi"
    782 	if err == nil {
    783 		t.Fatal("expected error")
    784 	}
    785 	const want = `template: top:7:20: executing "three" at <index "hi" $>: error calling index: index out of range: 5`
    786 	got := err.Error()
    787 	if got != want {
    788 		t.Errorf("expected\n%q\ngot\n%q", want, got)
    789 	}
    790 }
    791 
    792 func TestJSEscaping(t *testing.T) {
    793 	testCases := []struct {
    794 		in, exp string
    795 	}{
    796 		{`a`, `a`},
    797 		{`'foo`, `\'foo`},
    798 		{`Go "jump" \`, `Go \"jump\" \\`},
    799 		{`Yukihiro says ""`, `Yukihiro says \"\"`},
    800 		{"unprintable \uFDFF", `unprintable \uFDFF`},
    801 		{`<html>`, `\x3Chtml\x3E`},
    802 	}
    803 	for _, tc := range testCases {
    804 		s := JSEscapeString(tc.in)
    805 		if s != tc.exp {
    806 			t.Errorf("JS escaping [%s] got [%s] want [%s]", tc.in, s, tc.exp)
    807 		}
    808 	}
    809 }
    810 
    811 // A nice example: walk a binary tree.
    812 
    813 type Tree struct {
    814 	Val         int
    815 	Left, Right *Tree
    816 }
    817 
    818 // Use different delimiters to test Set.Delims.
    819 // Also test the trimming of leading and trailing spaces.
    820 const treeTemplate = `
    821 	(- define "tree" -)
    822 	[
    823 		(- .Val -)
    824 		(- with .Left -)
    825 			(template "tree" . -)
    826 		(- end -)
    827 		(- with .Right -)
    828 			(- template "tree" . -)
    829 		(- end -)
    830 	]
    831 	(- end -)
    832 `
    833 
    834 func TestTree(t *testing.T) {
    835 	var tree = &Tree{
    836 		1,
    837 		&Tree{
    838 			2, &Tree{
    839 				3,
    840 				&Tree{
    841 					4, nil, nil,
    842 				},
    843 				nil,
    844 			},
    845 			&Tree{
    846 				5,
    847 				&Tree{
    848 					6, nil, nil,
    849 				},
    850 				nil,
    851 			},
    852 		},
    853 		&Tree{
    854 			7,
    855 			&Tree{
    856 				8,
    857 				&Tree{
    858 					9, nil, nil,
    859 				},
    860 				nil,
    861 			},
    862 			&Tree{
    863 				10,
    864 				&Tree{
    865 					11, nil, nil,
    866 				},
    867 				nil,
    868 			},
    869 		},
    870 	}
    871 	tmpl, err := New("root").Delims("(", ")").Parse(treeTemplate)
    872 	if err != nil {
    873 		t.Fatal("parse error:", err)
    874 	}
    875 	var b bytes.Buffer
    876 	const expect = "[1[2[3[4]][5[6]]][7[8[9]][10[11]]]]"
    877 	// First by looking up the template.
    878 	err = tmpl.Lookup("tree").Execute(&b, tree)
    879 	if err != nil {
    880 		t.Fatal("exec error:", err)
    881 	}
    882 	result := b.String()
    883 	if result != expect {
    884 		t.Errorf("expected %q got %q", expect, result)
    885 	}
    886 	// Then direct to execution.
    887 	b.Reset()
    888 	err = tmpl.ExecuteTemplate(&b, "tree", tree)
    889 	if err != nil {
    890 		t.Fatal("exec error:", err)
    891 	}
    892 	result = b.String()
    893 	if result != expect {
    894 		t.Errorf("expected %q got %q", expect, result)
    895 	}
    896 }
    897 
    898 func TestExecuteOnNewTemplate(t *testing.T) {
    899 	// This is issue 3872.
    900 	New("Name").Templates()
    901 	// This is issue 11379.
    902 	new(Template).Templates()
    903 	new(Template).Parse("")
    904 	new(Template).New("abc").Parse("")
    905 	new(Template).Execute(nil, nil)                // returns an error (but does not crash)
    906 	new(Template).ExecuteTemplate(nil, "XXX", nil) // returns an error (but does not crash)
    907 }
    908 
    909 const testTemplates = `{{define "one"}}one{{end}}{{define "two"}}two{{end}}`
    910 
    911 func TestMessageForExecuteEmpty(t *testing.T) {
    912 	// Test a truly empty template.
    913 	tmpl := New("empty")
    914 	var b bytes.Buffer
    915 	err := tmpl.Execute(&b, 0)
    916 	if err == nil {
    917 		t.Fatal("expected initial error")
    918 	}
    919 	got := err.Error()
    920 	want := `template: empty: "empty" is an incomplete or empty template`
    921 	if got != want {
    922 		t.Errorf("expected error %s got %s", want, got)
    923 	}
    924 	// Add a non-empty template to check that the error is helpful.
    925 	tests, err := New("").Parse(testTemplates)
    926 	if err != nil {
    927 		t.Fatal(err)
    928 	}
    929 	tmpl.AddParseTree("secondary", tests.Tree)
    930 	err = tmpl.Execute(&b, 0)
    931 	if err == nil {
    932 		t.Fatal("expected second error")
    933 	}
    934 	got = err.Error()
    935 	want = `template: empty: "empty" is an incomplete or empty template`
    936 	if got != want {
    937 		t.Errorf("expected error %s got %s", want, got)
    938 	}
    939 	// Make sure we can execute the secondary.
    940 	err = tmpl.ExecuteTemplate(&b, "secondary", 0)
    941 	if err != nil {
    942 		t.Fatal(err)
    943 	}
    944 }
    945 
    946 func TestFinalForPrintf(t *testing.T) {
    947 	tmpl, err := New("").Parse(`{{"x" | printf}}`)
    948 	if err != nil {
    949 		t.Fatal(err)
    950 	}
    951 	var b bytes.Buffer
    952 	err = tmpl.Execute(&b, 0)
    953 	if err != nil {
    954 		t.Fatal(err)
    955 	}
    956 }
    957 
    958 type cmpTest struct {
    959 	expr  string
    960 	truth string
    961 	ok    bool
    962 }
    963 
    964 var cmpTests = []cmpTest{
    965 	{"eq true true", "true", true},
    966 	{"eq true false", "false", true},
    967 	{"eq 1+2i 1+2i", "true", true},
    968 	{"eq 1+2i 1+3i", "false", true},
    969 	{"eq 1.5 1.5", "true", true},
    970 	{"eq 1.5 2.5", "false", true},
    971 	{"eq 1 1", "true", true},
    972 	{"eq 1 2", "false", true},
    973 	{"eq `xy` `xy`", "true", true},
    974 	{"eq `xy` `xyz`", "false", true},
    975 	{"eq .Uthree .Uthree", "true", true},
    976 	{"eq .Uthree .Ufour", "false", true},
    977 	{"eq 3 4 5 6 3", "true", true},
    978 	{"eq 3 4 5 6 7", "false", true},
    979 	{"ne true true", "false", true},
    980 	{"ne true false", "true", true},
    981 	{"ne 1+2i 1+2i", "false", true},
    982 	{"ne 1+2i 1+3i", "true", true},
    983 	{"ne 1.5 1.5", "false", true},
    984 	{"ne 1.5 2.5", "true", true},
    985 	{"ne 1 1", "false", true},
    986 	{"ne 1 2", "true", true},
    987 	{"ne `xy` `xy`", "false", true},
    988 	{"ne `xy` `xyz`", "true", true},
    989 	{"ne .Uthree .Uthree", "false", true},
    990 	{"ne .Uthree .Ufour", "true", true},
    991 	{"lt 1.5 1.5", "false", true},
    992 	{"lt 1.5 2.5", "true", true},
    993 	{"lt 1 1", "false", true},
    994 	{"lt 1 2", "true", true},
    995 	{"lt `xy` `xy`", "false", true},
    996 	{"lt `xy` `xyz`", "true", true},
    997 	{"lt .Uthree .Uthree", "false", true},
    998 	{"lt .Uthree .Ufour", "true", true},
    999 	{"le 1.5 1.5", "true", true},
   1000 	{"le 1.5 2.5", "true", true},
   1001 	{"le 2.5 1.5", "false", true},
   1002 	{"le 1 1", "true", true},
   1003 	{"le 1 2", "true", true},
   1004 	{"le 2 1", "false", true},
   1005 	{"le `xy` `xy`", "true", true},
   1006 	{"le `xy` `xyz`", "true", true},
   1007 	{"le `xyz` `xy`", "false", true},
   1008 	{"le .Uthree .Uthree", "true", true},
   1009 	{"le .Uthree .Ufour", "true", true},
   1010 	{"le .Ufour .Uthree", "false", true},
   1011 	{"gt 1.5 1.5", "false", true},
   1012 	{"gt 1.5 2.5", "false", true},
   1013 	{"gt 1 1", "false", true},
   1014 	{"gt 2 1", "true", true},
   1015 	{"gt 1 2", "false", true},
   1016 	{"gt `xy` `xy`", "false", true},
   1017 	{"gt `xy` `xyz`", "false", true},
   1018 	{"gt .Uthree .Uthree", "false", true},
   1019 	{"gt .Uthree .Ufour", "false", true},
   1020 	{"gt .Ufour .Uthree", "true", true},
   1021 	{"ge 1.5 1.5", "true", true},
   1022 	{"ge 1.5 2.5", "false", true},
   1023 	{"ge 2.5 1.5", "true", true},
   1024 	{"ge 1 1", "true", true},
   1025 	{"ge 1 2", "false", true},
   1026 	{"ge 2 1", "true", true},
   1027 	{"ge `xy` `xy`", "true", true},
   1028 	{"ge `xy` `xyz`", "false", true},
   1029 	{"ge `xyz` `xy`", "true", true},
   1030 	{"ge .Uthree .Uthree", "true", true},
   1031 	{"ge .Uthree .Ufour", "false", true},
   1032 	{"ge .Ufour .Uthree", "true", true},
   1033 	// Mixing signed and unsigned integers.
   1034 	{"eq .Uthree .Three", "true", true},
   1035 	{"eq .Three .Uthree", "true", true},
   1036 	{"le .Uthree .Three", "true", true},
   1037 	{"le .Three .Uthree", "true", true},
   1038 	{"ge .Uthree .Three", "true", true},
   1039 	{"ge .Three .Uthree", "true", true},
   1040 	{"lt .Uthree .Three", "false", true},
   1041 	{"lt .Three .Uthree", "false", true},
   1042 	{"gt .Uthree .Three", "false", true},
   1043 	{"gt .Three .Uthree", "false", true},
   1044 	{"eq .Ufour .Three", "false", true},
   1045 	{"lt .Ufour .Three", "false", true},
   1046 	{"gt .Ufour .Three", "true", true},
   1047 	{"eq .NegOne .Uthree", "false", true},
   1048 	{"eq .Uthree .NegOne", "false", true},
   1049 	{"ne .NegOne .Uthree", "true", true},
   1050 	{"ne .Uthree .NegOne", "true", true},
   1051 	{"lt .NegOne .Uthree", "true", true},
   1052 	{"lt .Uthree .NegOne", "false", true},
   1053 	{"le .NegOne .Uthree", "true", true},
   1054 	{"le .Uthree .NegOne", "false", true},
   1055 	{"gt .NegOne .Uthree", "false", true},
   1056 	{"gt .Uthree .NegOne", "true", true},
   1057 	{"ge .NegOne .Uthree", "false", true},
   1058 	{"ge .Uthree .NegOne", "true", true},
   1059 	{"eq (index `x` 0) 'x'", "true", true}, // The example that triggered this rule.
   1060 	{"eq (index `x` 0) 'y'", "false", true},
   1061 	// Errors
   1062 	{"eq `xy` 1", "", false},    // Different types.
   1063 	{"eq 2 2.0", "", false},     // Different types.
   1064 	{"lt true true", "", false}, // Unordered types.
   1065 	{"lt 1+0i 1+0i", "", false}, // Unordered types.
   1066 }
   1067 
   1068 func TestComparison(t *testing.T) {
   1069 	b := new(bytes.Buffer)
   1070 	var cmpStruct = struct {
   1071 		Uthree, Ufour uint
   1072 		NegOne, Three int
   1073 	}{3, 4, -1, 3}
   1074 	for _, test := range cmpTests {
   1075 		text := fmt.Sprintf("{{if %s}}true{{else}}false{{end}}", test.expr)
   1076 		tmpl, err := New("empty").Parse(text)
   1077 		if err != nil {
   1078 			t.Fatalf("%q: %s", test.expr, err)
   1079 		}
   1080 		b.Reset()
   1081 		err = tmpl.Execute(b, &cmpStruct)
   1082 		if test.ok && err != nil {
   1083 			t.Errorf("%s errored incorrectly: %s", test.expr, err)
   1084 			continue
   1085 		}
   1086 		if !test.ok && err == nil {
   1087 			t.Errorf("%s did not error", test.expr)
   1088 			continue
   1089 		}
   1090 		if b.String() != test.truth {
   1091 			t.Errorf("%s: want %s; got %s", test.expr, test.truth, b.String())
   1092 		}
   1093 	}
   1094 }
   1095 
   1096 func TestMissingMapKey(t *testing.T) {
   1097 	data := map[string]int{
   1098 		"x": 99,
   1099 	}
   1100 	tmpl, err := New("t1").Parse("{{.x}} {{.y}}")
   1101 	if err != nil {
   1102 		t.Fatal(err)
   1103 	}
   1104 	var b bytes.Buffer
   1105 	// By default, just get "<no value>"
   1106 	err = tmpl.Execute(&b, data)
   1107 	if err != nil {
   1108 		t.Fatal(err)
   1109 	}
   1110 	want := "99 <no value>"
   1111 	got := b.String()
   1112 	if got != want {
   1113 		t.Errorf("got %q; expected %q", got, want)
   1114 	}
   1115 	// Same if we set the option explicitly to the default.
   1116 	tmpl.Option("missingkey=default")
   1117 	b.Reset()
   1118 	err = tmpl.Execute(&b, data)
   1119 	if err != nil {
   1120 		t.Fatal("default:", err)
   1121 	}
   1122 	want = "99 <no value>"
   1123 	got = b.String()
   1124 	if got != want {
   1125 		t.Errorf("got %q; expected %q", got, want)
   1126 	}
   1127 	// Next we ask for a zero value
   1128 	tmpl.Option("missingkey=zero")
   1129 	b.Reset()
   1130 	err = tmpl.Execute(&b, data)
   1131 	if err != nil {
   1132 		t.Fatal("zero:", err)
   1133 	}
   1134 	want = "99 0"
   1135 	got = b.String()
   1136 	if got != want {
   1137 		t.Errorf("got %q; expected %q", got, want)
   1138 	}
   1139 	// Now we ask for an error.
   1140 	tmpl.Option("missingkey=error")
   1141 	err = tmpl.Execute(&b, data)
   1142 	if err == nil {
   1143 		t.Errorf("expected error; got none")
   1144 	}
   1145 	// same Option, but now a nil interface: ask for an error
   1146 	err = tmpl.Execute(&b, nil)
   1147 	t.Log(err)
   1148 	if err == nil {
   1149 		t.Errorf("expected error for nil-interface; got none")
   1150 	}
   1151 }
   1152 
   1153 // Test that the error message for multiline unterminated string
   1154 // refers to the line number of the opening quote.
   1155 func TestUnterminatedStringError(t *testing.T) {
   1156 	_, err := New("X").Parse("hello\n\n{{`unterminated\n\n\n\n}}\n some more\n\n")
   1157 	if err == nil {
   1158 		t.Fatal("expected error")
   1159 	}
   1160 	str := err.Error()
   1161 	if !strings.Contains(str, "X:3: unexpected unterminated raw quoted string") {
   1162 		t.Fatalf("unexpected error: %s", str)
   1163 	}
   1164 }
   1165 
   1166 const alwaysErrorText = "always be failing"
   1167 
   1168 var alwaysError = errors.New(alwaysErrorText)
   1169 
   1170 type ErrorWriter int
   1171 
   1172 func (e ErrorWriter) Write(p []byte) (int, error) {
   1173 	return 0, alwaysError
   1174 }
   1175 
   1176 func TestExecuteGivesExecError(t *testing.T) {
   1177 	// First, a non-execution error shouldn't be an ExecError.
   1178 	tmpl, err := New("X").Parse("hello")
   1179 	if err != nil {
   1180 		t.Fatal(err)
   1181 	}
   1182 	err = tmpl.Execute(ErrorWriter(0), 0)
   1183 	if err == nil {
   1184 		t.Fatal("expected error; got none")
   1185 	}
   1186 	if err.Error() != alwaysErrorText {
   1187 		t.Errorf("expected %q error; got %q", alwaysErrorText, err)
   1188 	}
   1189 	// This one should be an ExecError.
   1190 	tmpl, err = New("X").Parse("hello, {{.X.Y}}")
   1191 	if err != nil {
   1192 		t.Fatal(err)
   1193 	}
   1194 	err = tmpl.Execute(ioutil.Discard, 0)
   1195 	if err == nil {
   1196 		t.Fatal("expected error; got none")
   1197 	}
   1198 	eerr, ok := err.(ExecError)
   1199 	if !ok {
   1200 		t.Fatalf("did not expect ExecError %s", eerr)
   1201 	}
   1202 	expect := "field X in type int"
   1203 	if !strings.Contains(err.Error(), expect) {
   1204 		t.Errorf("expected %q; got %q", expect, err)
   1205 	}
   1206 }
   1207 
   1208 func funcNameTestFunc() int {
   1209 	return 0
   1210 }
   1211 
   1212 func TestGoodFuncNames(t *testing.T) {
   1213 	names := []string{
   1214 		"_",
   1215 		"a",
   1216 		"a1",
   1217 		"a1",
   1218 		"",
   1219 	}
   1220 	for _, name := range names {
   1221 		tmpl := New("X").Funcs(
   1222 			FuncMap{
   1223 				name: funcNameTestFunc,
   1224 			},
   1225 		)
   1226 		if tmpl == nil {
   1227 			t.Fatalf("nil result for %q", name)
   1228 		}
   1229 	}
   1230 }
   1231 
   1232 func TestBadFuncNames(t *testing.T) {
   1233 	names := []string{
   1234 		"",
   1235 		"2",
   1236 		"a-b",
   1237 	}
   1238 	for _, name := range names {
   1239 		testBadFuncName(name, t)
   1240 	}
   1241 }
   1242 
   1243 func testBadFuncName(name string, t *testing.T) {
   1244 	defer func() {
   1245 		recover()
   1246 	}()
   1247 	New("X").Funcs(
   1248 		FuncMap{
   1249 			name: funcNameTestFunc,
   1250 		},
   1251 	)
   1252 	// If we get here, the name did not cause a panic, which is how Funcs
   1253 	// reports an error.
   1254 	t.Errorf("%q succeeded incorrectly as function name", name)
   1255 }
   1256 
   1257 func TestBlock(t *testing.T) {
   1258 	const (
   1259 		input   = `a({{block "inner" .}}bar({{.}})baz{{end}})b`
   1260 		want    = `a(bar(hello)baz)b`
   1261 		overlay = `{{define "inner"}}foo({{.}})bar{{end}}`
   1262 		want2   = `a(foo(goodbye)bar)b`
   1263 	)
   1264 	tmpl, err := New("outer").Parse(input)
   1265 	if err != nil {
   1266 		t.Fatal(err)
   1267 	}
   1268 	tmpl2, err := Must(tmpl.Clone()).Parse(overlay)
   1269 	if err != nil {
   1270 		t.Fatal(err)
   1271 	}
   1272 
   1273 	var buf bytes.Buffer
   1274 	if err := tmpl.Execute(&buf, "hello"); err != nil {
   1275 		t.Fatal(err)
   1276 	}
   1277 	if got := buf.String(); got != want {
   1278 		t.Errorf("got %q, want %q", got, want)
   1279 	}
   1280 
   1281 	buf.Reset()
   1282 	if err := tmpl2.Execute(&buf, "goodbye"); err != nil {
   1283 		t.Fatal(err)
   1284 	}
   1285 	if got := buf.String(); got != want2 {
   1286 		t.Errorf("got %q, want %q", got, want2)
   1287 	}
   1288 }
   1289 
   1290 // Check that calling an invalid field on nil pointer prints
   1291 // a field error instead of a distracting nil pointer error.
   1292 // https://golang.org/issue/15125
   1293 func TestMissingFieldOnNil(t *testing.T) {
   1294 	tmpl := Must(New("tmpl").Parse("{{.MissingField}}"))
   1295 	var d *T
   1296 	err := tmpl.Execute(ioutil.Discard, d)
   1297 	got := "<nil>"
   1298 	if err != nil {
   1299 		got = err.Error()
   1300 	}
   1301 	want := "can't evaluate field MissingField in type *template.T"
   1302 	if !strings.HasSuffix(got, want) {
   1303 		t.Errorf("got error %q, want %q", got, want)
   1304 	}
   1305 }
   1306 
   1307 func TestMaxExecDepth(t *testing.T) {
   1308 	tmpl := Must(New("tmpl").Parse(`{{template "tmpl" .}}`))
   1309 	err := tmpl.Execute(ioutil.Discard, nil)
   1310 	got := "<nil>"
   1311 	if err != nil {
   1312 		got = err.Error()
   1313 	}
   1314 	const want = "exceeded maximum template depth"
   1315 	if !strings.Contains(got, want) {
   1316 		t.Errorf("got error %q; want %q", got, want)
   1317 	}
   1318 }
   1319 
   1320 func TestAddrOfIndex(t *testing.T) {
   1321 	// golang.org/issue/14916.
   1322 	// Before index worked on reflect.Values, the .String could not be
   1323 	// found on the (incorrectly unaddressable) V value,
   1324 	// in contrast to range, which worked fine.
   1325 	// Also testing that passing a reflect.Value to tmpl.Execute works.
   1326 	texts := []string{
   1327 		`{{range .}}{{.String}}{{end}}`,
   1328 		`{{with index . 0}}{{.String}}{{end}}`,
   1329 	}
   1330 	for _, text := range texts {
   1331 		tmpl := Must(New("tmpl").Parse(text))
   1332 		var buf bytes.Buffer
   1333 		err := tmpl.Execute(&buf, reflect.ValueOf([]V{{1}}))
   1334 		if err != nil {
   1335 			t.Fatalf("%s: Execute: %v", text, err)
   1336 		}
   1337 		if buf.String() != "<1>" {
   1338 			t.Fatalf("%s: template output = %q, want %q", text, &buf, "<1>")
   1339 		}
   1340 	}
   1341 }
   1342 
   1343 func TestInterfaceValues(t *testing.T) {
   1344 	// golang.org/issue/17714.
   1345 	// Before index worked on reflect.Values, interface values
   1346 	// were always implicitly promoted to the underlying value,
   1347 	// except that nil interfaces were promoted to the zero reflect.Value.
   1348 	// Eliminating a round trip to interface{} and back to reflect.Value
   1349 	// eliminated this promotion, breaking these cases.
   1350 	tests := []struct {
   1351 		text string
   1352 		out  string
   1353 	}{
   1354 		{`{{index .Nil 1}}`, "ERROR: index of untyped nil"},
   1355 		{`{{index .Slice 2}}`, "2"},
   1356 		{`{{index .Slice .Two}}`, "2"},
   1357 		{`{{call .Nil 1}}`, "ERROR: call of nil"},
   1358 		{`{{call .PlusOne 1}}`, "2"},
   1359 		{`{{call .PlusOne .One}}`, "2"},
   1360 		{`{{and (index .Slice 0) true}}`, "0"},
   1361 		{`{{and .Zero true}}`, "0"},
   1362 		{`{{and (index .Slice 1) false}}`, "false"},
   1363 		{`{{and .One false}}`, "false"},
   1364 		{`{{or (index .Slice 0) false}}`, "false"},
   1365 		{`{{or .Zero false}}`, "false"},
   1366 		{`{{or (index .Slice 1) true}}`, "1"},
   1367 		{`{{or .One true}}`, "1"},
   1368 		{`{{not (index .Slice 0)}}`, "true"},
   1369 		{`{{not .Zero}}`, "true"},
   1370 		{`{{not (index .Slice 1)}}`, "false"},
   1371 		{`{{not .One}}`, "false"},
   1372 		{`{{eq (index .Slice 0) .Zero}}`, "true"},
   1373 		{`{{eq (index .Slice 1) .One}}`, "true"},
   1374 		{`{{ne (index .Slice 0) .Zero}}`, "false"},
   1375 		{`{{ne (index .Slice 1) .One}}`, "false"},
   1376 		{`{{ge (index .Slice 0) .One}}`, "false"},
   1377 		{`{{ge (index .Slice 1) .Zero}}`, "true"},
   1378 		{`{{gt (index .Slice 0) .One}}`, "false"},
   1379 		{`{{gt (index .Slice 1) .Zero}}`, "true"},
   1380 		{`{{le (index .Slice 0) .One}}`, "true"},
   1381 		{`{{le (index .Slice 1) .Zero}}`, "false"},
   1382 		{`{{lt (index .Slice 0) .One}}`, "true"},
   1383 		{`{{lt (index .Slice 1) .Zero}}`, "false"},
   1384 	}
   1385 
   1386 	for _, tt := range tests {
   1387 		tmpl := Must(New("tmpl").Parse(tt.text))
   1388 		var buf bytes.Buffer
   1389 		err := tmpl.Execute(&buf, map[string]interface{}{
   1390 			"PlusOne": func(n int) int {
   1391 				return n + 1
   1392 			},
   1393 			"Slice": []int{0, 1, 2, 3},
   1394 			"One":   1,
   1395 			"Two":   2,
   1396 			"Nil":   nil,
   1397 			"Zero":  0,
   1398 		})
   1399 		if strings.HasPrefix(tt.out, "ERROR:") {
   1400 			e := strings.TrimSpace(strings.TrimPrefix(tt.out, "ERROR:"))
   1401 			if err == nil || !strings.Contains(err.Error(), e) {
   1402 				t.Errorf("%s: Execute: %v, want error %q", tt.text, err, e)
   1403 			}
   1404 			continue
   1405 		}
   1406 		if err != nil {
   1407 			t.Errorf("%s: Execute: %v", tt.text, err)
   1408 			continue
   1409 		}
   1410 		if buf.String() != tt.out {
   1411 			t.Errorf("%s: template output = %q, want %q", tt.text, &buf, tt.out)
   1412 		}
   1413 	}
   1414 }
   1415