libgo/go/text/template/exec_test.go

   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 var tSliceOfNil = []*T{nil}
 151
 152 // A non-empty interface.
 153 type I interface {
 154         Method0() string
 155 }
 156
 157 var iVal I = tVal
 158
 159 // Helpers for creation.
 160 func newInt(n int) *int {
 161         return &n
 162 }
 163
 164 func newString(s string) *string {
 165         return &s
 166 }
 167
 168 func newIntSlice(n ...int) *[]int {
 169         p := new([]int)
 170         *p = make([]int, len(n))
 171         copy(*p, n)
 172         return p
 173 }
 174
 175 // Simple methods with and without arguments.
 176 func (t *T) Method0() string {
 177         return "M0"
 178 }
 179
 180 func (t *T) Method1(a int) int {
 181         return a
 182 }
 183
 184 func (t *T) Method2(a uint16, b string) string {
 185         return fmt.Sprintf("Method2: %d %s", a, b)
 186 }
 187
 188 func (t *T) Method3(v interface{}) string {
 189         return fmt.Sprintf("Method3: %v", v)
 190 }
 191
 192 func (t *T) Copy() *T {
 193         n := new(T)
 194         *n = *t
 195         return n
 196 }
 197
 198 func (t *T) MAdd(a int, b []int) []int {
 199         v := make([]int, len(b))
 200         for i, x := range b {
 201                 v[i] = x + a
 202         }
 203         return v
 204 }
 205
 206 var myError = errors.New("my error")
 207
 208 // MyError returns a value and an error according to its argument.
 209 func (t *T) MyError(error bool) (bool, error) {
 210         if error {
 211                 return true, myError
 212         }
 213         return false, nil
 214 }
 215
 216 // A few methods to test chaining.
 217 func (t *T) GetU() *U {
 218         return t.U
 219 }
 220
 221 func (u *U) TrueFalse(b bool) string {
 222         if b {
 223                 return "true"
 224         }
 225         return ""
 226 }
 227
 228 func typeOf(arg interface{}) string {
 229         return fmt.Sprintf("%T", arg)
 230 }
 231
 232 type execTest struct {
 233         name   string
 234         input  string
 235         output string
 236         data   interface{}
 237         ok     bool
 238 }
 239
 240 // bigInt and bigUint are hex string representing numbers either side
 241 // of the max int boundary.
 242 // We do it this way so the test doesn't depend on ints being 32 bits.
 243 var (
 244         bigInt  = fmt.Sprintf("0x%x", int(1<<uint(reflect.TypeOf(0).Bits()-1)-1))
 245         bigUint = fmt.Sprintf("0x%x", uint(1<<uint(reflect.TypeOf(0).Bits()-1)))
 246 )
 247
 248 var execTests = []execTest{
 249         // Trivial cases.
 250         {"empty", "", "", nil, true},
 251         {"text", "some text", "some text", nil, true},
 252         {"nil action", "{{nil}}", "", nil, false},
 253
 254         // Ideal constants.
 255         {"ideal int", "{{typeOf 3}}", "int", 0, true},
 256         {"ideal float", "{{typeOf 1.0}}", "float64", 0, true},
 257         {"ideal exp float", "{{typeOf 1e1}}", "float64", 0, true},
 258         {"ideal complex", "{{typeOf 1i}}", "complex128", 0, true},
 259         {"ideal int", "{{typeOf " + bigInt + "}}", "int", 0, true},
 260         {"ideal too big", "{{typeOf " + bigUint + "}}", "", 0, false},
 261         {"ideal nil without type", "{{nil}}", "", 0, false},
 262
 263         // Fields of structs.
 264         {".X", "-{{.X}}-", "-x-", tVal, true},
 265         {".U.V", "-{{.U.V}}-", "-v-", tVal, true},
 266         {".unexported", "{{.unexported}}", "", tVal, false},
 267
 268         // Fields on maps.
 269         {"map .one", "{{.MSI.one}}", "1", tVal, true},
 270         {"map .two", "{{.MSI.two}}", "2", tVal, true},
 271         {"map .NO", "{{.MSI.NO}}", "<no value>", tVal, true},
 272         {"map .one interface", "{{.MXI.one}}", "1", tVal, true},
 273         {"map .WRONG args", "{{.MSI.one 1}}", "", tVal, false},
 274         {"map .WRONG type", "{{.MII.one}}", "", tVal, false},
 275
 276         // Dots of all kinds to test basic evaluation.
 277         {"dot int", "<{{.}}>", "<13>", 13, true},
 278         {"dot uint", "<{{.}}>", "<14>", uint(14), true},
 279         {"dot float", "<{{.}}>", "<15.1>", 15.1, true},
 280         {"dot bool", "<{{.}}>", "<true>", true, true},
 281         {"dot complex", "<{{.}}>", "<(16.2-17i)>", 16.2 - 17i, true},
 282         {"dot string", "<{{.}}>", "<hello>", "hello", true},
 283         {"dot slice", "<{{.}}>", "<[-1 -2 -3]>", []int{-1, -2, -3}, true},
 284         {"dot map", "<{{.}}>", "<map[two:22]>", map[string]int{"two": 22}, true},
 285         {"dot struct", "<{{.}}>", "<{7 seven}>", struct {
 286                 a int
 287                 b string
 288         }{7, "seven"}, true},
 289
 290         // Variables.
 291         {"$ int", "{{$}}", "123", 123, true},
 292         {"$.I", "{{$.I}}", "17", tVal, true},
 293         {"$.U.V", "{{$.U.V}}", "v", tVal, true},
 294         {"declare in action", "{{$x := $.U.V}}{{$x}}", "v", tVal, true},
 295
 296         // Type with String method.
 297         {"V{6666}.String()", "-{{.V0}}-", "-<6666>-", tVal, true},
 298         {"&V{7777}.String()", "-{{.V1}}-", "-<7777>-", tVal, true},
 299         {"(*V)(nil).String()", "-{{.V2}}-", "-nilV-", tVal, true},
 300
 301         // Type with Error method.
 302         {"W{888}.Error()", "-{{.W0}}-", "-[888]-", tVal, true},
 303         {"&W{999}.Error()", "-{{.W1}}-", "-[999]-", tVal, true},
 304         {"(*W)(nil).Error()", "-{{.W2}}-", "-nilW-", tVal, true},
 305
 306         // Pointers.
 307         {"*int", "{{.PI}}", "23", tVal, true},
 308         {"*string", "{{.PS}}", "a string", tVal, true},
 309         {"*[]int", "{{.PSI}}", "[21 22 23]", tVal, true},
 310         {"*[]int[1]", "{{index .PSI 1}}", "22", tVal, true},
 311         {"NIL", "{{.NIL}}", "<nil>", tVal, true},
 312
 313         // Empty interfaces holding values.
 314         {"empty nil", "{{.Empty0}}", "<no value>", tVal, true},
 315         {"empty with int", "{{.Empty1}}", "3", tVal, true},
 316         {"empty with string", "{{.Empty2}}", "empty2", tVal, true},
 317         {"empty with slice", "{{.Empty3}}", "[7 8]", tVal, true},
 318         {"empty with struct", "{{.Empty4}}", "{UinEmpty}", tVal, true},
 319         {"empty with struct, field", "{{.Empty4.V}}", "UinEmpty", tVal, true},
 320
 321         // Method calls.
 322         {".Method0", "-{{.Method0}}-", "-M0-", tVal, true},
 323         {".Method1(1234)", "-{{.Method1 1234}}-", "-1234-", tVal, true},
 324         {".Method1(.I)", "-{{.Method1 .I}}-", "-17-", tVal, true},
 325         {".Method2(3, .X)", "-{{.Method2 3 .X}}-", "-Method2: 3 x-", tVal, true},
 326         {".Method2(.U16, `str`)", "-{{.Method2 .U16 `str`}}-", "-Method2: 16 str-", tVal, true},
 327         {".Method2(.U16, $x)", "{{if $x := .X}}-{{.Method2 .U16 $x}}{{end}}-", "-Method2: 16 x-", tVal, true},
 328         {".Method3(nil constant)", "-{{.Method3 nil}}-", "-Method3: <nil>-", tVal, true},
 329         {".Method3(nil value)", "-{{.Method3 .MXI.unset}}-", "-Method3: <nil>-", tVal, true},
 330         {"method on var", "{{if $x := .}}-{{$x.Method2 .U16 $x.X}}{{end}}-", "-Method2: 16 x-", tVal, true},
 331         {"method on chained var",
 332                 "{{range .MSIone}}{{if $.U.TrueFalse $.True}}{{$.U.TrueFalse $.True}}{{else}}WRONG{{end}}{{end}}",
 333                 "true", tVal, true},
 334         {"chained method",
 335                 "{{range .MSIone}}{{if $.GetU.TrueFalse $.True}}{{$.U.TrueFalse $.True}}{{else}}WRONG{{end}}{{end}}",
 336                 "true", tVal, true},
 337         {"chained method on variable",
 338                 "{{with $x := .}}{{with .SI}}{{$.GetU.TrueFalse $.True}}{{end}}{{end}}",
 339                 "true", tVal, true},
 340         {".NilOKFunc not nil", "{{call .NilOKFunc .PI}}", "false", tVal, true},
 341         {".NilOKFunc nil", "{{call .NilOKFunc nil}}", "true", tVal, true},
 342         {"method on nil value from slice", "-{{range .}}{{.Method1 1234}}{{end}}-", "-1234-", tSliceOfNil, true},
 343
 344         // Function call builtin.
 345         {".BinaryFunc", "{{call .BinaryFunc `1` `2`}}", "[1=2]", tVal, true},
 346         {".VariadicFunc0", "{{call .VariadicFunc}}", "<>", tVal, true},
 347         {".VariadicFunc2", "{{call .VariadicFunc `he` `llo`}}", "<he+llo>", tVal, true},
 348         {".VariadicFuncInt", "{{call .VariadicFuncInt 33 `he` `llo`}}", "33=<he+llo>", tVal, true},
 349         {"if .BinaryFunc call", "{{ if .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{end}}", "[1=2]", tVal, true},
 350         {"if not .BinaryFunc call", "{{ if not .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{else}}No{{end}}", "No", tVal, true},
 351         {"Interface Call", `{{stringer .S}}`, "foozle", map[string]interface{}{"S": bytes.NewBufferString("foozle")}, true},
 352         {".ErrFunc", "{{call .ErrFunc}}", "bla", tVal, true},
 353         {"call nil", "{{call nil}}", "", tVal, false},
 354
 355         // Erroneous function calls (check args).
 356         {".BinaryFuncTooFew", "{{call .BinaryFunc `1`}}", "", tVal, false},
 357         {".BinaryFuncTooMany", "{{call .BinaryFunc `1` `2` `3`}}", "", tVal, false},
 358         {".BinaryFuncBad0", "{{call .BinaryFunc 1 3}}", "", tVal, false},
 359         {".BinaryFuncBad1", "{{call .BinaryFunc `1` 3}}", "", tVal, false},
 360         {".VariadicFuncBad0", "{{call .VariadicFunc 3}}", "", tVal, false},
 361         {".VariadicFuncIntBad0", "{{call .VariadicFuncInt}}", "", tVal, false},
 362         {".VariadicFuncIntBad`", "{{call .VariadicFuncInt `x`}}", "", tVal, false},
 363         {".VariadicFuncNilBad", "{{call .VariadicFunc nil}}", "", tVal, false},
 364
 365         // Pipelines.
 366         {"pipeline", "-{{.Method0 | .Method2 .U16}}-", "-Method2: 16 M0-", tVal, true},
 367         {"pipeline func", "-{{call .VariadicFunc `llo` | call .VariadicFunc `he` }}-", "-<he+<llo>>-", tVal, true},
 368
 369         // Parenthesized expressions
 370         {"parens in pipeline", "{{printf `%d %d %d` (1) (2 | add 3) (add 4 (add 5 6))}}", "1 5 15", tVal, true},
 371
 372         // Parenthesized expressions with field accesses
 373         {"parens: $ in paren", "{{($).X}}", "x", tVal, true},
 374         {"parens: $.GetU in paren", "{{($.GetU).V}}", "v", tVal, true},
 375         {"parens: $ in paren in pipe", "{{($ | echo).X}}", "x", tVal, true},
 376         {"parens: spaces and args", `{{(makemap "up" "down" "left" "right").left}}`, "right", tVal, true},
 377
 378         // If.
 379         {"if true", "{{if true}}TRUE{{end}}", "TRUE", tVal, true},
 380         {"if false", "{{if false}}TRUE{{else}}FALSE{{end}}", "FALSE", tVal, true},
 381         {"if nil", "{{if nil}}TRUE{{end}}", "", tVal, false},
 382         {"if 1", "{{if 1}}NON-ZERO{{else}}ZERO{{end}}", "NON-ZERO", tVal, true},
 383         {"if 0", "{{if 0}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
 384         {"if 1.5", "{{if 1.5}}NON-ZERO{{else}}ZERO{{end}}", "NON-ZERO", tVal, true},
 385         {"if 0.0", "{{if .FloatZero}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
 386         {"if 1.5i", "{{if 1.5i}}NON-ZERO{{else}}ZERO{{end}}", "NON-ZERO", tVal, true},
 387         {"if 0.0i", "{{if .ComplexZero}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
 388         {"if emptystring", "{{if ``}}NON-EMPTY{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
 389         {"if string", "{{if `notempty`}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
 390         {"if emptyslice", "{{if .SIEmpty}}NON-EMPTY{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
 391         {"if slice", "{{if .SI}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
 392         {"if emptymap", "{{if .MSIEmpty}}NON-EMPTY{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
 393         {"if map", "{{if .MSI}}NON-EMPTY{{else}}EMPTY{{end}}", "NON-EMPTY", tVal, true},
 394         {"if map unset", "{{if .MXI.none}}NON-ZERO{{else}}ZERO{{end}}", "ZERO", tVal, true},
 395         {"if map not unset", "{{if not .MXI.none}}ZERO{{else}}NON-ZERO{{end}}", "ZERO", tVal, true},
 396         {"if $x with $y int", "{{if $x := true}}{{with $y := .I}}{{$x}},{{$y}}{{end}}{{end}}", "true,17", tVal, true},
 397         {"if $x with $x int", "{{if $x := true}}{{with $x := .I}}{{$x}},{{end}}{{$x}}{{end}}", "17,true", tVal, true},
 398         {"if else if", "{{if false}}FALSE{{else if true}}TRUE{{end}}", "TRUE", tVal, true},
 399         {"if else chain", "{{if eq 1 3}}1{{else if eq 2 3}}2{{else if eq 3 3}}3{{end}}", "3", tVal, true},
 400
 401         // Print etc.
 402         {"print", `{{print "hello, print"}}`, "hello, print", tVal, true},
 403         {"print 123", `{{print 1 2 3}}`, "1 2 3", tVal, true},
 404         {"print nil", `{{print nil}}`, "<nil>", tVal, true},
 405         {"println", `{{println 1 2 3}}`, "1 2 3\n", tVal, true},
 406         {"printf int", `{{printf "%04x" 127}}`, "007f", tVal, true},
 407         {"printf float", `{{printf "%g" 3.5}}`, "3.5", tVal, true},
 408         {"printf complex", `{{printf "%g" 1+7i}}`, "(1+7i)", tVal, true},
 409         {"printf string", `{{printf "%s" "hello"}}`, "hello", tVal, true},
 410         {"printf function", `{{printf "%#q" zeroArgs}}`, "`zeroArgs`", tVal, true},
 411         {"printf field", `{{printf "%s" .U.V}}`, "v", tVal, true},
 412         {"printf method", `{{printf "%s" .Method0}}`, "M0", tVal, true},
 413         {"printf dot", `{{with .I}}{{printf "%d" .}}{{end}}`, "17", tVal, true},
 414         {"printf var", `{{with $x := .I}}{{printf "%d" $x}}{{end}}`, "17", tVal, true},
 415         {"printf lots", `{{printf "%d %s %g %s" 127 "hello" 7-3i .Method0}}`, "127 hello (7-3i) M0", tVal, true},
 416
 417         // HTML.
 418         {"html", `{{html "<script>alert(\"XSS\");</script>"}}`,
 419                 "&lt;script&gt;alert(&#34;XSS&#34;);&lt;/script&gt;", nil, true},
 420         {"html pipeline", `{{printf "<script>alert(\"XSS\");</script>" | html}}`,
 421                 "&lt;script&gt;alert(&#34;XSS&#34;);&lt;/script&gt;", nil, true},
 422         {"html", `{{html .PS}}`, "a string", tVal, true},
 423
 424         // JavaScript.
 425         {"js", `{{js .}}`, `It\'d be nice.`, `It'd be nice.`, true},
 426
 427         // URL query.
 428         {"urlquery", `{{"http://www.example.org/"|urlquery}}`, "http%3A%2F%2Fwww.example.org%2F", nil, true},
 429
 430         // Booleans
 431         {"not", "{{not true}} {{not false}}", "false true", nil, true},
 432         {"and", "{{and false 0}} {{and 1 0}} {{and 0 true}} {{and 1 1}}", "false 0 0 1", nil, true},
 433         {"or", "{{or 0 0}} {{or 1 0}} {{or 0 true}} {{or 1 1}}", "0 1 true 1", nil, true},
 434         {"boolean if", "{{if and true 1 `hi`}}TRUE{{else}}FALSE{{end}}", "TRUE", tVal, true},
 435         {"boolean if not", "{{if and true 1 `hi` | not}}TRUE{{else}}FALSE{{end}}", "FALSE", nil, true},
 436
 437         // Indexing.
 438         {"slice[0]", "{{index .SI 0}}", "3", tVal, true},
 439         {"slice[1]", "{{index .SI 1}}", "4", tVal, true},
 440         {"slice[HUGE]", "{{index .SI 10}}", "", tVal, false},
 441         {"slice[WRONG]", "{{index .SI `hello`}}", "", tVal, false},
 442         {"slice[nil]", "{{index .SI nil}}", "", tVal, false},
 443         {"map[one]", "{{index .MSI `one`}}", "1", tVal, true},
 444         {"map[two]", "{{index .MSI `two`}}", "2", tVal, true},
 445         {"map[NO]", "{{index .MSI `XXX`}}", "0", tVal, true},
 446         {"map[nil]", "{{index .MSI nil}}", "", tVal, false},
 447         {"map[``]", "{{index .MSI ``}}", "0", tVal, true},
 448         {"map[WRONG]", "{{index .MSI 10}}", "", tVal, false},
 449         {"double index", "{{index .SMSI 1 `eleven`}}", "11", tVal, true},
 450         {"nil[1]", "{{index nil 1}}", "", tVal, false},
 451
 452         // Len.
 453         {"slice", "{{len .SI}}", "3", tVal, true},
 454         {"map", "{{len .MSI }}", "3", tVal, true},
 455         {"len of int", "{{len 3}}", "", tVal, false},
 456         {"len of nothing", "{{len .Empty0}}", "", tVal, false},
 457
 458         // With.
 459         {"with true", "{{with true}}{{.}}{{end}}", "true", tVal, true},
 460         {"with false", "{{with false}}{{.}}{{else}}FALSE{{end}}", "FALSE", tVal, true},
 461         {"with 1", "{{with 1}}{{.}}{{else}}ZERO{{end}}", "1", tVal, true},
 462         {"with 0", "{{with 0}}{{.}}{{else}}ZERO{{end}}", "ZERO", tVal, true},
 463         {"with 1.5", "{{with 1.5}}{{.}}{{else}}ZERO{{end}}", "1.5", tVal, true},
 464         {"with 0.0", "{{with .FloatZero}}{{.}}{{else}}ZERO{{end}}", "ZERO", tVal, true},
 465         {"with 1.5i", "{{with 1.5i}}{{.}}{{else}}ZERO{{end}}", "(0+1.5i)", tVal, true},
 466         {"with 0.0i", "{{with .ComplexZero}}{{.}}{{else}}ZERO{{end}}", "ZERO", tVal, true},
 467         {"with emptystring", "{{with ``}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
 468         {"with string", "{{with `notempty`}}{{.}}{{else}}EMPTY{{end}}", "notempty", tVal, true},
 469         {"with emptyslice", "{{with .SIEmpty}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
 470         {"with slice", "{{with .SI}}{{.}}{{else}}EMPTY{{end}}", "[3 4 5]", tVal, true},
 471         {"with emptymap", "{{with .MSIEmpty}}{{.}}{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
 472         {"with map", "{{with .MSIone}}{{.}}{{else}}EMPTY{{end}}", "map[one:1]", tVal, true},
 473         {"with empty interface, struct field", "{{with .Empty4}}{{.V}}{{end}}", "UinEmpty", tVal, true},
 474         {"with $x int", "{{with $x := .I}}{{$x}}{{end}}", "17", tVal, true},
 475         {"with $x struct.U.V", "{{with $x := $}}{{$x.U.V}}{{end}}", "v", tVal, true},
 476         {"with variable and action", "{{with $x := $}}{{$y := $.U.V}}{{$y}}{{end}}", "v", tVal, true},
 477
 478         // Range.
 479         {"range []int", "{{range .SI}}-{{.}}-{{end}}", "-3--4--5-", tVal, true},
 480         {"range empty no else", "{{range .SIEmpty}}-{{.}}-{{end}}", "", tVal, true},
 481         {"range []int else", "{{range .SI}}-{{.}}-{{else}}EMPTY{{end}}", "-3--4--5-", tVal, true},
 482         {"range empty else", "{{range .SIEmpty}}-{{.}}-{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
 483         {"range []bool", "{{range .SB}}-{{.}}-{{end}}", "-true--false-", tVal, true},
 484         {"range []int method", "{{range .SI | .MAdd .I}}-{{.}}-{{end}}", "-20--21--22-", tVal, true},
 485         {"range map", "{{range .MSI}}-{{.}}-{{end}}", "-1--3--2-", tVal, true},
 486         {"range empty map no else", "{{range .MSIEmpty}}-{{.}}-{{end}}", "", tVal, true},
 487         {"range map else", "{{range .MSI}}-{{.}}-{{else}}EMPTY{{end}}", "-1--3--2-", tVal, true},
 488         {"range empty map else", "{{range .MSIEmpty}}-{{.}}-{{else}}EMPTY{{end}}", "EMPTY", tVal, true},
 489         {"range empty interface", "{{range .Empty3}}-{{.}}-{{else}}EMPTY{{end}}", "-7--8-", tVal, true},
 490         {"range empty nil", "{{range .Empty0}}-{{.}}-{{end}}", "", tVal, true},
 491         {"range $x SI", "{{range $x := .SI}}<{{$x}}>{{end}}", "<3><4><5>", tVal, true},
 492         {"range $x $y SI", "{{range $x, $y := .SI}}<{{$x}}={{$y}}>{{end}}", "<0=3><1=4><2=5>", tVal, true},
 493         {"range $x MSIone", "{{range $x := .MSIone}}<{{$x}}>{{end}}", "<1>", tVal, true},
 494         {"range $x $y MSIone", "{{range $x, $y := .MSIone}}<{{$x}}={{$y}}>{{end}}", "<one=1>", tVal, true},
 495         {"range $x PSI", "{{range $x := .PSI}}<{{$x}}>{{end}}", "<21><22><23>", tVal, true},
 496         {"declare in range", "{{range $x := .PSI}}<{{$foo:=$x}}{{$x}}>{{end}}", "<21><22><23>", tVal, true},
 497         {"range count", `{{range $i, $x := count 5}}[{{$i}}]{{$x}}{{end}}`, "[0]a[1]b[2]c[3]d[4]e", tVal, true},
 498         {"range nil count", `{{range $i, $x := count 0}}{{else}}empty{{end}}`, "empty", tVal, true},
 499
 500         // Cute examples.
 501         {"or as if true", `{{or .SI "slice is empty"}}`, "[3 4 5]", tVal, true},
 502         {"or as if false", `{{or .SIEmpty "slice is empty"}}`, "slice is empty", tVal, true},
 503
 504         // Error handling.
 505         {"error method, error", "{{.MyError true}}", "", tVal, false},
 506         {"error method, no error", "{{.MyError false}}", "false", tVal, true},
 507
 508         // Fixed bugs.
 509         // Must separate dot and receiver; otherwise args are evaluated with dot set to variable.
 510         {"bug0", "{{range .MSIone}}{{if $.Method1 .}}X{{end}}{{end}}", "X", tVal, true},
 511         // Do not loop endlessly in indirect for non-empty interfaces.
 512         // The bug appears with *interface only; looped forever.
 513         {"bug1", "{{.Method0}}", "M0", &iVal, true},
 514         // Was taking address of interface field, so method set was empty.
 515         {"bug2", "{{$.NonEmptyInterface.Method0}}", "M0", tVal, true},
 516         // Struct values were not legal in with - mere oversight.
 517         {"bug3", "{{with $}}{{.Method0}}{{end}}", "M0", tVal, true},
 518         // Nil interface values in if.
 519         {"bug4", "{{if .Empty0}}non-nil{{else}}nil{{end}}", "nil", tVal, true},
 520         // Stringer.
 521         {"bug5", "{{.Str}}", "foozle", tVal, true},
 522         {"bug5a", "{{.Err}}", "erroozle", tVal, true},
 523         // Args need to be indirected and dereferenced sometimes.
 524         {"bug6a", "{{vfunc .V0 .V1}}", "vfunc", tVal, true},
 525         {"bug6b", "{{vfunc .V0 .V0}}", "vfunc", tVal, true},
 526         {"bug6c", "{{vfunc .V1 .V0}}", "vfunc", tVal, true},
 527         {"bug6d", "{{vfunc .V1 .V1}}", "vfunc", tVal, true},
 528         // Legal parse but illegal execution: non-function should have no arguments.
 529         {"bug7a", "{{3 2}}", "", tVal, false},
 530         {"bug7b", "{{$x := 1}}{{$x 2}}", "", tVal, false},
 531         {"bug7c", "{{$x := 1}}{{3 | $x}}", "", tVal, false},
 532         // Pipelined arg was not being type-checked.
 533         {"bug8a", "{{3|oneArg}}", "", tVal, false},
 534         {"bug8b", "{{4|dddArg 3}}", "", tVal, false},
 535         // A bug was introduced that broke map lookups for lower-case names.
 536         {"bug9", "{{.cause}}", "neglect", map[string]string{"cause": "neglect"}, true},
 537         // Field chain starting with function did not work.
 538         {"bug10", "{{mapOfThree.three}}-{{(mapOfThree).three}}", "3-3", 0, true},
 539         // Dereferencing nil pointer while evaluating function arguments should not panic. Issue 7333.
 540         {"bug11", "{{valueString .PS}}", "", T{}, false},
 541         // 0xef gave constant type float64. Issue 8622.
 542         {"bug12xe", "{{printf `%T` 0xef}}", "int", T{}, true},
 543         {"bug12xE", "{{printf `%T` 0xEE}}", "int", T{}, true},
 544         {"bug12Xe", "{{printf `%T` 0Xef}}", "int", T{}, true},
 545         {"bug12XE", "{{printf `%T` 0XEE}}", "int", T{}, true},
 546         // Chained nodes did not work as arguments. Issue 8473.
 547         {"bug13", "{{print (.Copy).I}}", "17", tVal, true},
 548         // Didn't protect against nil or literal values in field chains.
 549         {"bug14a", "{{(nil).True}}", "", tVal, false},
 550         {"bug14b", "{{$x := nil}}{{$x.anything}}", "", tVal, false},
 551         {"bug14c", `{{$x := (1.0)}}{{$y := ("hello")}}{{$x.anything}}{{$y.true}}`, "", tVal, false},
 552         // Didn't call validateType on function results. Issue 10800.
 553         {"bug15", "{{valueString returnInt}}", "", tVal, false},
 554         // Variadic function corner cases. Issue 10946.
 555         {"bug16a", "{{true|printf}}", "", tVal, false},
 556         {"bug16b", "{{1|printf}}", "", tVal, false},
 557         {"bug16c", "{{1.1|printf}}", "", tVal, false},
 558         {"bug16d", "{{'x'|printf}}", "", tVal, false},
 559         {"bug16e", "{{0i|printf}}", "", tVal, false},
 560         {"bug16f", "{{true|twoArgs \"xxx\"}}", "", tVal, false},
 561         {"bug16g", "{{\"aaa\" |twoArgs \"bbb\"}}", "twoArgs=bbbaaa", tVal, true},
 562         {"bug16h", "{{1|oneArg}}", "", tVal, false},
 563         {"bug16i", "{{\"aaa\"|oneArg}}", "oneArg=aaa", tVal, true},
 564         {"bug16j", "{{1+2i|printf \"%v\"}}", "(1+2i)", tVal, true},
 565         {"bug16k", "{{\"aaa\"|printf }}", "aaa", tVal, true},
 566         {"bug17a", "{{.NonEmptyInterface.X}}", "x", tVal, true},
 567         {"bug17b", "-{{.NonEmptyInterface.Method1 1234}}-", "-1234-", tVal, true},
 568         {"bug17c", "{{len .NonEmptyInterfacePtS}}", "2", tVal, true},
 569         {"bug17d", "{{index .NonEmptyInterfacePtS 0}}", "a", tVal, true},
 570         {"bug17e", "{{range .NonEmptyInterfacePtS}}-{{.}}-{{end}}", "-a--b-", tVal, true},
 571 }
 572
 573 func zeroArgs() string {
 574         return "zeroArgs"
 575 }
 576
 577 func oneArg(a string) string {
 578         return "oneArg=" + a
 579 }
 580
 581 func twoArgs(a, b string) string {
 582         return "twoArgs=" + a + b
 583 }
 584
 585 func dddArg(a int, b ...string) string {
 586         return fmt.Sprintln(a, b)
 587 }
 588
 589 // count returns a channel that will deliver n sequential 1-letter strings starting at "a"
 590 func count(n int) chan string {
 591         if n == 0 {
 592                 return nil
 593         }
 594         c := make(chan string)
 595         go func() {
 596                 for i := 0; i < n; i++ {
 597                         c <- "abcdefghijklmnop"[i : i+1]
 598                 }
 599                 close(c)
 600         }()
 601         return c
 602 }
 603
 604 // vfunc takes a *V and a V
 605 func vfunc(V, *V) string {
 606         return "vfunc"
 607 }
 608
 609 // valueString takes a string, not a pointer.
 610 func valueString(v string) string {
 611         return "value is ignored"
 612 }
 613
 614 // returnInt returns an int
 615 func returnInt() int {
 616         return 7
 617 }
 618
 619 func add(args ...int) int {
 620         sum := 0
 621         for _, x := range args {
 622                 sum += x
 623         }
 624         return sum
 625 }
 626
 627 func echo(arg interface{}) interface{} {
 628         return arg
 629 }
 630
 631 func makemap(arg ...string) map[string]string {
 632         if len(arg)%2 != 0 {
 633                 panic("bad makemap")
 634         }
 635         m := make(map[string]string)
 636         for i := 0; i < len(arg); i += 2 {
 637                 m[arg[i]] = arg[i+1]
 638         }
 639         return m
 640 }
 641
 642 func stringer(s fmt.Stringer) string {
 643         return s.String()
 644 }
 645
 646 func mapOfThree() interface{} {
 647         return map[string]int{"three": 3}
 648 }
 649
 650 func testExecute(execTests []execTest, template *Template, t *testing.T) {
 651         b := new(bytes.Buffer)
 652         funcs := FuncMap{
 653                 "add":         add,
 654                 "count":       count,
 655                 "dddArg":      dddArg,
 656                 "echo":        echo,
 657                 "makemap":     makemap,
 658                 "mapOfThree":  mapOfThree,
 659                 "oneArg":      oneArg,
 660                 "returnInt":   returnInt,
 661                 "stringer":    stringer,
 662                 "twoArgs":     twoArgs,
 663                 "typeOf":      typeOf,
 664                 "valueString": valueString,
 665                 "vfunc":       vfunc,
 666                 "zeroArgs":    zeroArgs,
 667         }
 668         for _, test := range execTests {
 669                 var tmpl *Template
 670                 var err error
 671                 if template == nil {
 672                         tmpl, err = New(test.name).Funcs(funcs).Parse(test.input)
 673                 } else {
 674                         tmpl, err = template.New(test.name).Funcs(funcs).Parse(test.input)
 675                 }
 676                 if err != nil {
 677                         t.Errorf("%s: parse error: %s", test.name, err)
 678                         continue
 679                 }
 680                 b.Reset()
 681                 err = tmpl.Execute(b, test.data)
 682                 switch {
 683                 case !test.ok && err == nil:
 684                         t.Errorf("%s: expected error; got none", test.name)
 685                         continue
 686                 case test.ok && err != nil:
 687                         t.Errorf("%s: unexpected execute error: %s", test.name, err)
 688                         continue
 689                 case !test.ok && err != nil:
 690                         // expected error, got one
 691                         if *debug {
 692                                 fmt.Printf("%s: %s\n\t%s\n", test.name, test.input, err)
 693                         }
 694                 }
 695                 result := b.String()
 696                 if result != test.output {
 697                         t.Errorf("%s: expected\n\t%q\ngot\n\t%q", test.name, test.output, result)
 698                 }
 699         }
 700 }
 701
 702 func TestExecute(t *testing.T) {
 703         testExecute(execTests, nil, t)
 704 }
 705
 706 var delimPairs = []string{
 707         "", "", // default
 708         "{{", "}}", // same as default
 709         "<<", ">>", // distinct
 710         "|", "|", // same
 711         "(日)", "(本)", // peculiar
 712 }
 713
 714 func TestDelims(t *testing.T) {
 715         const hello = "Hello, world"
 716         var value = struct{ Str string }{hello}
 717         for i := 0; i < len(delimPairs); i += 2 {
 718                 text := ".Str"
 719                 left := delimPairs[i+0]
 720                 trueLeft := left
 721                 right := delimPairs[i+1]
 722                 trueRight := right
 723                 if left == "" { // default case
 724                         trueLeft = "{{"
 725                 }
 726                 if right == "" { // default case
 727                         trueRight = "}}"
 728                 }
 729                 text = trueLeft + text + trueRight
 730                 // Now add a comment
 731                 text += trueLeft + "/*comment*/" + trueRight
 732                 // Now add  an action containing a string.
 733                 text += trueLeft + `"` + trueLeft + `"` + trueRight
 734                 // At this point text looks like `{{.Str}}{{/*comment*/}}{{"{{"}}`.
 735                 tmpl, err := New("delims").Delims(left, right).Parse(text)
 736                 if err != nil {
 737                         t.Fatalf("delim %q text %q parse err %s", left, text, err)
 738                 }
 739                 var b = new(bytes.Buffer)
 740                 err = tmpl.Execute(b, value)
 741                 if err != nil {
 742                         t.Fatalf("delim %q exec err %s", left, err)
 743                 }
 744                 if b.String() != hello+trueLeft {
 745                         t.Errorf("expected %q got %q", hello+trueLeft, b.String())
 746                 }
 747         }
 748 }
 749
 750 // Check that an error from a method flows back to the top.
 751 func TestExecuteError(t *testing.T) {
 752         b := new(bytes.Buffer)
 753         tmpl := New("error")
 754         _, err := tmpl.Parse("{{.MyError true}}")
 755         if err != nil {
 756                 t.Fatalf("parse error: %s", err)
 757         }
 758         err = tmpl.Execute(b, tVal)
 759         if err == nil {
 760                 t.Errorf("expected error; got none")
 761         } else if !strings.Contains(err.Error(), myError.Error()) {
 762                 if *debug {
 763                         fmt.Printf("test execute error: %s\n", err)
 764                 }
 765                 t.Errorf("expected myError; got %s", err)
 766         }
 767 }
 768
 769 const execErrorText = `line 1
 770 line 2
 771 line 3
 772 {{template "one" .}}
 773 {{define "one"}}{{template "two" .}}{{end}}
 774 {{define "two"}}{{template "three" .}}{{end}}
 775 {{define "three"}}{{index "hi" $}}{{end}}`
 776
 777 // Check that an error from a nested template contains all the relevant information.
 778 func TestExecError(t *testing.T) {
 779         tmpl, err := New("top").Parse(execErrorText)
 780         if err != nil {
 781                 t.Fatal("parse error:", err)
 782         }
 783         var b bytes.Buffer
 784         err = tmpl.Execute(&b, 5) // 5 is out of range indexing "hi"
 785         if err == nil {
 786                 t.Fatal("expected error")
 787         }
 788         const want = `template: top:7:20: executing "three" at <index "hi" $>: error calling index: index out of range: 5`
 789         got := err.Error()
 790         if got != want {
 791                 t.Errorf("expected\n%q\ngot\n%q", want, got)
 792         }
 793 }
 794
 795 func TestJSEscaping(t *testing.T) {
 796         testCases := []struct {
 797                 in, exp string
 798         }{
 799                 {`a`, `a`},
 800                 {`'foo`, `\'foo`},
 801                 {`Go "jump" \`, `Go \"jump\" \\`},
 802                 {`Yukihiro says "今日は世界"`, `Yukihiro says \"今日は世界\"`},
 803                 {"unprintable \uFDFF", `unprintable \uFDFF`},
 804                 {`<html>`, `\x3Chtml\x3E`},
 805         }
 806         for _, tc := range testCases {
 807                 s := JSEscapeString(tc.in)
 808                 if s != tc.exp {
 809                         t.Errorf("JS escaping [%s] got [%s] want [%s]", tc.in, s, tc.exp)
 810                 }
 811         }
 812 }
 813
 814 // A nice example: walk a binary tree.
 815
 816 type Tree struct {
 817         Val         int
 818         Left, Right *Tree
 819 }
 820
 821 // Use different delimiters to test Set.Delims.
 822 // Also test the trimming of leading and trailing spaces.
 823 const treeTemplate = `
 824         (- define "tree" -)
 825         [
 826                 (- .Val -)
 827                 (- with .Left -)
 828                         (template "tree" . -)
 829                 (- end -)
 830                 (- with .Right -)
 831                         (- template "tree" . -)
 832                 (- end -)
 833         ]
 834         (- end -)
 835 `
 836
 837 func TestTree(t *testing.T) {
 838         var tree = &Tree{
 839                 1,
 840                 &Tree{
 841                         2, &Tree{
 842                                 3,
 843                                 &Tree{
 844                                         4, nil, nil,
 845                                 },
 846                                 nil,
 847                         },
 848                         &Tree{
 849                                 5,
 850                                 &Tree{
 851                                         6, nil, nil,
 852                                 },
 853                                 nil,
 854                         },
 855                 },
 856                 &Tree{
 857                         7,
 858                         &Tree{
 859                                 8,
 860                                 &Tree{
 861                                         9, nil, nil,
 862                                 },
 863                                 nil,
 864                         },
 865                         &Tree{
 866                                 10,
 867                                 &Tree{
 868                                         11, nil, nil,
 869                                 },
 870                                 nil,
 871                         },
 872                 },
 873         }
 874         tmpl, err := New("root").Delims("(", ")").Parse(treeTemplate)
 875         if err != nil {
 876                 t.Fatal("parse error:", err)
 877         }
 878         var b bytes.Buffer
 879         const expect = "[1[2[3[4]][5[6]]][7[8[9]][10[11]]]]"
 880         // First by looking up the template.
 881         err = tmpl.Lookup("tree").Execute(&b, tree)
 882         if err != nil {
 883                 t.Fatal("exec error:", err)
 884         }
 885         result := b.String()
 886         if result != expect {
 887                 t.Errorf("expected %q got %q", expect, result)
 888         }
 889         // Then direct to execution.
 890         b.Reset()
 891         err = tmpl.ExecuteTemplate(&b, "tree", tree)
 892         if err != nil {
 893                 t.Fatal("exec error:", err)
 894         }
 895         result = b.String()
 896         if result != expect {
 897                 t.Errorf("expected %q got %q", expect, result)
 898         }
 899 }
 900
 901 func TestExecuteOnNewTemplate(t *testing.T) {
 902         // This is issue 3872.
 903         New("Name").Templates()
 904         // This is issue 11379.
 905         new(Template).Templates()
 906         new(Template).Parse("")
 907         new(Template).New("abc").Parse("")
 908         new(Template).Execute(nil, nil)                // returns an error (but does not crash)
 909         new(Template).ExecuteTemplate(nil, "XXX", nil) // returns an error (but does not crash)
 910 }
 911
 912 const testTemplates = `{{define "one"}}one{{end}}{{define "two"}}two{{end}}`
 913
 914 func TestMessageForExecuteEmpty(t *testing.T) {
 915         // Test a truly empty template.
 916         tmpl := New("empty")
 917         var b bytes.Buffer
 918         err := tmpl.Execute(&b, 0)
 919         if err == nil {
 920                 t.Fatal("expected initial error")
 921         }
 922         got := err.Error()
 923         want := `template: empty: "empty" is an incomplete or empty template`
 924         if got != want {
 925                 t.Errorf("expected error %s got %s", want, got)
 926         }
 927         // Add a non-empty template to check that the error is helpful.
 928         tests, err := New("").Parse(testTemplates)
 929         if err != nil {
 930                 t.Fatal(err)
 931         }
 932         tmpl.AddParseTree("secondary", tests.Tree)
 933         err = tmpl.Execute(&b, 0)
 934         if err == nil {
 935                 t.Fatal("expected second error")
 936         }
 937         got = err.Error()
 938         want = `template: empty: "empty" is an incomplete or empty template`
 939         if got != want {
 940                 t.Errorf("expected error %s got %s", want, got)
 941         }
 942         // Make sure we can execute the secondary.
 943         err = tmpl.ExecuteTemplate(&b, "secondary", 0)
 944         if err != nil {
 945                 t.Fatal(err)
 946         }
 947 }
 948
 949 func TestFinalForPrintf(t *testing.T) {
 950         tmpl, err := New("").Parse(`{{"x" | printf}}`)
 951         if err != nil {
 952                 t.Fatal(err)
 953         }
 954         var b bytes.Buffer
 955         err = tmpl.Execute(&b, 0)
 956         if err != nil {
 957                 t.Fatal(err)
 958         }
 959 }
 960
 961 type cmpTest struct {
 962         expr  string
 963         truth string
 964         ok    bool
 965 }
 966
 967 var cmpTests = []cmpTest{
 968         {"eq true true", "true", true},
 969         {"eq true false", "false", true},
 970         {"eq 1+2i 1+2i", "true", true},
 971         {"eq 1+2i 1+3i", "false", true},
 972         {"eq 1.5 1.5", "true", true},
 973         {"eq 1.5 2.5", "false", true},
 974         {"eq 1 1", "true", true},
 975         {"eq 1 2", "false", true},
 976         {"eq `xy` `xy`", "true", true},
 977         {"eq `xy` `xyz`", "false", true},
 978         {"eq .Uthree .Uthree", "true", true},
 979         {"eq .Uthree .Ufour", "false", true},
 980         {"eq 3 4 5 6 3", "true", true},
 981         {"eq 3 4 5 6 7", "false", true},
 982         {"ne true true", "false", true},
 983         {"ne true false", "true", true},
 984         {"ne 1+2i 1+2i", "false", true},
 985         {"ne 1+2i 1+3i", "true", true},
 986         {"ne 1.5 1.5", "false", true},
 987         {"ne 1.5 2.5", "true", true},
 988         {"ne 1 1", "false", true},
 989         {"ne 1 2", "true", true},
 990         {"ne `xy` `xy`", "false", true},
 991         {"ne `xy` `xyz`", "true", true},
 992         {"ne .Uthree .Uthree", "false", true},
 993         {"ne .Uthree .Ufour", "true", true},
 994         {"lt 1.5 1.5", "false", true},
 995         {"lt 1.5 2.5", "true", true},
 996         {"lt 1 1", "false", true},
 997         {"lt 1 2", "true", true},
 998         {"lt `xy` `xy`", "false", true},
 999         {"lt `xy` `xyz`", "true", true},
1000         {"lt .Uthree .Uthree", "false", true},
1001         {"lt .Uthree .Ufour", "true", true},
1002         {"le 1.5 1.5", "true", true},
1003         {"le 1.5 2.5", "true", true},
1004         {"le 2.5 1.5", "false", true},
1005         {"le 1 1", "true", true},
1006         {"le 1 2", "true", true},
1007         {"le 2 1", "false", true},
1008         {"le `xy` `xy`", "true", true},
1009         {"le `xy` `xyz`", "true", true},
1010         {"le `xyz` `xy`", "false", true},
1011         {"le .Uthree .Uthree", "true", true},
1012         {"le .Uthree .Ufour", "true", true},
1013         {"le .Ufour .Uthree", "false", true},
1014         {"gt 1.5 1.5", "false", true},
1015         {"gt 1.5 2.5", "false", true},
1016         {"gt 1 1", "false", true},
1017         {"gt 2 1", "true", true},
1018         {"gt 1 2", "false", true},
1019         {"gt `xy` `xy`", "false", true},
1020         {"gt `xy` `xyz`", "false", true},
1021         {"gt .Uthree .Uthree", "false", true},
1022         {"gt .Uthree .Ufour", "false", true},
1023         {"gt .Ufour .Uthree", "true", true},
1024         {"ge 1.5 1.5", "true", true},
1025         {"ge 1.5 2.5", "false", true},
1026         {"ge 2.5 1.5", "true", true},
1027         {"ge 1 1", "true", true},
1028         {"ge 1 2", "false", true},
1029         {"ge 2 1", "true", true},
1030         {"ge `xy` `xy`", "true", true},
1031         {"ge `xy` `xyz`", "false", true},
1032         {"ge `xyz` `xy`", "true", true},
1033         {"ge .Uthree .Uthree", "true", true},
1034         {"ge .Uthree .Ufour", "false", true},
1035         {"ge .Ufour .Uthree", "true", true},
1036         // Mixing signed and unsigned integers.
1037         {"eq .Uthree .Three", "true", true},
1038         {"eq .Three .Uthree", "true", true},
1039         {"le .Uthree .Three", "true", true},
1040         {"le .Three .Uthree", "true", true},
1041         {"ge .Uthree .Three", "true", true},
1042         {"ge .Three .Uthree", "true", true},
1043         {"lt .Uthree .Three", "false", true},
1044         {"lt .Three .Uthree", "false", true},
1045         {"gt .Uthree .Three", "false", true},
1046         {"gt .Three .Uthree", "false", true},
1047         {"eq .Ufour .Three", "false", true},
1048         {"lt .Ufour .Three", "false", true},
1049         {"gt .Ufour .Three", "true", true},
1050         {"eq .NegOne .Uthree", "false", true},
1051         {"eq .Uthree .NegOne", "false", true},
1052         {"ne .NegOne .Uthree", "true", true},
1053         {"ne .Uthree .NegOne", "true", true},
1054         {"lt .NegOne .Uthree", "true", true},
1055         {"lt .Uthree .NegOne", "false", true},
1056         {"le .NegOne .Uthree", "true", true},
1057         {"le .Uthree .NegOne", "false", true},
1058         {"gt .NegOne .Uthree", "false", true},
1059         {"gt .Uthree .NegOne", "true", true},
1060         {"ge .NegOne .Uthree", "false", true},
1061         {"ge .Uthree .NegOne", "true", true},
1062         {"eq (index `x` 0) 'x'", "true", true}, // The example that triggered this rule.
1063         {"eq (index `x` 0) 'y'", "false", true},
1064         // Errors
1065         {"eq `xy` 1", "", false},    // Different types.
1066         {"eq 2 2.0", "", false},     // Different types.
1067         {"lt true true", "", false}, // Unordered types.
1068         {"lt 1+0i 1+0i", "", false}, // Unordered types.
1069 }
1070
1071 func TestComparison(t *testing.T) {
1072         b := new(bytes.Buffer)
1073         var cmpStruct = struct {
1074                 Uthree, Ufour uint
1075                 NegOne, Three int
1076         }{3, 4, -1, 3}
1077         for _, test := range cmpTests {
1078                 text := fmt.Sprintf("{{if %s}}true{{else}}false{{end}}", test.expr)
1079                 tmpl, err := New("empty").Parse(text)
1080                 if err != nil {
1081                         t.Fatalf("%q: %s", test.expr, err)
1082                 }
1083                 b.Reset()
1084                 err = tmpl.Execute(b, &cmpStruct)
1085                 if test.ok && err != nil {
1086                         t.Errorf("%s errored incorrectly: %s", test.expr, err)
1087                         continue
1088                 }
1089                 if !test.ok && err == nil {
1090                         t.Errorf("%s did not error", test.expr)
1091                         continue
1092                 }
1093                 if b.String() != test.truth {
1094                         t.Errorf("%s: want %s; got %s", test.expr, test.truth, b.String())
1095                 }
1096         }
1097 }
1098
1099 func TestMissingMapKey(t *testing.T) {
1100         data := map[string]int{
1101                 "x": 99,
1102         }
1103         tmpl, err := New("t1").Parse("{{.x}} {{.y}}")
1104         if err != nil {
1105                 t.Fatal(err)
1106         }
1107         var b bytes.Buffer
1108         // By default, just get "<no value>"
1109         err = tmpl.Execute(&b, data)
1110         if err != nil {
1111                 t.Fatal(err)
1112         }
1113         want := "99 <no value>"
1114         got := b.String()
1115         if got != want {
1116                 t.Errorf("got %q; expected %q", got, want)
1117         }
1118         // Same if we set the option explicitly to the default.
1119         tmpl.Option("missingkey=default")
1120         b.Reset()
1121         err = tmpl.Execute(&b, data)
1122         if err != nil {
1123                 t.Fatal("default:", err)
1124         }
1125         want = "99 <no value>"
1126         got = b.String()
1127         if got != want {
1128                 t.Errorf("got %q; expected %q", got, want)
1129         }
1130         // Next we ask for a zero value
1131         tmpl.Option("missingkey=zero")
1132         b.Reset()
1133         err = tmpl.Execute(&b, data)
1134         if err != nil {
1135                 t.Fatal("zero:", err)
1136         }
1137         want = "99 0"
1138         got = b.String()
1139         if got != want {
1140                 t.Errorf("got %q; expected %q", got, want)
1141         }
1142         // Now we ask for an error.
1143         tmpl.Option("missingkey=error")
1144         err = tmpl.Execute(&b, data)
1145         if err == nil {
1146                 t.Errorf("expected error; got none")
1147         }
1148         // same Option, but now a nil interface: ask for an error
1149         err = tmpl.Execute(&b, nil)
1150         t.Log(err)
1151         if err == nil {
1152                 t.Errorf("expected error for nil-interface; got none")
1153         }
1154 }
1155
1156 // Test that the error message for multiline unterminated string
1157 // refers to the line number of the opening quote.
1158 func TestUnterminatedStringError(t *testing.T) {
1159         _, err := New("X").Parse("hello\n\n{{`unterminated\n\n\n\n}}\n some more\n\n")
1160         if err == nil {
1161                 t.Fatal("expected error")
1162         }
1163         str := err.Error()
1164         if !strings.Contains(str, "X:3: unexpected unterminated raw quoted string") {
1165                 t.Fatalf("unexpected error: %s", str)
1166         }
1167 }
1168
1169 const alwaysErrorText = "always be failing"
1170
1171 var alwaysError = errors.New(alwaysErrorText)
1172
1173 type ErrorWriter int
1174
1175 func (e ErrorWriter) Write(p []byte) (int, error) {
1176         return 0, alwaysError
1177 }
1178
1179 func TestExecuteGivesExecError(t *testing.T) {
1180         // First, a non-execution error shouldn't be an ExecError.
1181         tmpl, err := New("X").Parse("hello")
1182         if err != nil {
1183                 t.Fatal(err)
1184         }
1185         err = tmpl.Execute(ErrorWriter(0), 0)
1186         if err == nil {
1187                 t.Fatal("expected error; got none")
1188         }
1189         if err.Error() != alwaysErrorText {
1190                 t.Errorf("expected %q error; got %q", alwaysErrorText, err)
1191         }
1192         // This one should be an ExecError.
1193         tmpl, err = New("X").Parse("hello, {{.X.Y}}")
1194         if err != nil {
1195                 t.Fatal(err)
1196         }
1197         err = tmpl.Execute(ioutil.Discard, 0)
1198         if err == nil {
1199                 t.Fatal("expected error; got none")
1200         }
1201         eerr, ok := err.(ExecError)
1202         if !ok {
1203                 t.Fatalf("did not expect ExecError %s", eerr)
1204         }
1205         expect := "field X in type int"
1206         if !strings.Contains(err.Error(), expect) {
1207                 t.Errorf("expected %q; got %q", expect, err)
1208         }
1209 }
1210
1211 func funcNameTestFunc() int {
1212         return 0
1213 }
1214
1215 func TestGoodFuncNames(t *testing.T) {
1216         names := []string{
1217                 "_",
1218                 "a",
1219                 "a1",
1220                 "a1",
1221                 "Ӵ",
1222         }
1223         for _, name := range names {
1224                 tmpl := New("X").Funcs(
1225                         FuncMap{
1226                                 name: funcNameTestFunc,
1227                         },
1228                 )
1229                 if tmpl == nil {
1230                         t.Fatalf("nil result for %q", name)
1231                 }
1232         }
1233 }
1234
1235 func TestBadFuncNames(t *testing.T) {
1236         names := []string{
1237                 "",
1238                 "2",
1239                 "a-b",
1240         }
1241         for _, name := range names {
1242                 testBadFuncName(name, t)
1243         }
1244 }
1245
1246 func testBadFuncName(name string, t *testing.T) {
1247         defer func() {
1248                 recover()
1249         }()
1250         New("X").Funcs(
1251                 FuncMap{
1252                         name: funcNameTestFunc,
1253                 },
1254         )
1255         // If we get here, the name did not cause a panic, which is how Funcs
1256         // reports an error.
1257         t.Errorf("%q succeeded incorrectly as function name", name)
1258 }
1259
1260 func TestBlock(t *testing.T) {
1261         const (
1262                 input   = `a({{block "inner" .}}bar({{.}})baz{{end}})b`
1263                 want    = `a(bar(hello)baz)b`
1264                 overlay = `{{define "inner"}}foo({{.}})bar{{end}}`
1265                 want2   = `a(foo(goodbye)bar)b`
1266         )
1267         tmpl, err := New("outer").Parse(input)
1268         if err != nil {
1269                 t.Fatal(err)
1270         }
1271         tmpl2, err := Must(tmpl.Clone()).Parse(overlay)
1272         if err != nil {
1273                 t.Fatal(err)
1274         }
1275
1276         var buf bytes.Buffer
1277         if err := tmpl.Execute(&buf, "hello"); err != nil {
1278                 t.Fatal(err)
1279         }
1280         if got := buf.String(); got != want {
1281                 t.Errorf("got %q, want %q", got, want)
1282         }
1283
1284         buf.Reset()
1285         if err := tmpl2.Execute(&buf, "goodbye"); err != nil {
1286                 t.Fatal(err)
1287         }
1288         if got := buf.String(); got != want2 {
1289                 t.Errorf("got %q, want %q", got, want2)
1290         }
1291 }
1292
1293 // Check that calling an invalid field on nil pointer prints
1294 // a field error instead of a distracting nil pointer error.
1295 // https://golang.org/issue/15125
1296 func TestMissingFieldOnNil(t *testing.T) {
1297         tmpl := Must(New("tmpl").Parse("{{.MissingField}}"))
1298         var d *T
1299         err := tmpl.Execute(ioutil.Discard, d)
1300         got := "<nil>"
1301         if err != nil {
1302                 got = err.Error()
1303         }
1304         want := "can't evaluate field MissingField in type *template.T"
1305         if !strings.HasSuffix(got, want) {
1306                 t.Errorf("got error %q, want %q", got, want)
1307         }
1308 }
1309
1310 func TestMaxExecDepth(t *testing.T) {
1311         tmpl := Must(New("tmpl").Parse(`{{template "tmpl" .}}`))
1312         err := tmpl.Execute(ioutil.Discard, nil)
1313         got := "<nil>"
1314         if err != nil {
1315                 got = err.Error()
1316         }
1317         const want = "exceeded maximum template depth"
1318         if !strings.Contains(got, want) {
1319                 t.Errorf("got error %q; want %q", got, want)
1320         }
1321 }
1322
1323 func TestAddrOfIndex(t *testing.T) {
1324         // golang.org/issue/14916.
1325         // Before index worked on reflect.Values, the .String could not be
1326         // found on the (incorrectly unaddressable) V value,
1327         // in contrast to range, which worked fine.
1328         // Also testing that passing a reflect.Value to tmpl.Execute works.
1329         texts := []string{
1330                 `{{range .}}{{.String}}{{end}}`,
1331                 `{{with index . 0}}{{.String}}{{end}}`,
1332         }
1333         for _, text := range texts {
1334                 tmpl := Must(New("tmpl").Parse(text))
1335                 var buf bytes.Buffer
1336                 err := tmpl.Execute(&buf, reflect.ValueOf([]V{{1}}))
1337                 if err != nil {
1338                         t.Fatalf("%s: Execute: %v", text, err)
1339                 }
1340                 if buf.String() != "<1>" {
1341                         t.Fatalf("%s: template output = %q, want %q", text, &buf, "<1>")
1342                 }
1343         }
1344 }
1345
1346 func TestInterfaceValues(t *testing.T) {
1347         // golang.org/issue/17714.
1348         // Before index worked on reflect.Values, interface values
1349         // were always implicitly promoted to the underlying value,
1350         // except that nil interfaces were promoted to the zero reflect.Value.
1351         // Eliminating a round trip to interface{} and back to reflect.Value
1352         // eliminated this promotion, breaking these cases.
1353         tests := []struct {
1354                 text string
1355                 out  string
1356         }{
1357                 {`{{index .Nil 1}}`, "ERROR: index of untyped nil"},
1358                 {`{{index .Slice 2}}`, "2"},
1359                 {`{{index .Slice .Two}}`, "2"},
1360                 {`{{call .Nil 1}}`, "ERROR: call of nil"},
1361                 {`{{call .PlusOne 1}}`, "2"},
1362                 {`{{call .PlusOne .One}}`, "2"},
1363                 {`{{and (index .Slice 0) true}}`, "0"},
1364                 {`{{and .Zero true}}`, "0"},
1365                 {`{{and (index .Slice 1) false}}`, "false"},
1366                 {`{{and .One false}}`, "false"},
1367                 {`{{or (index .Slice 0) false}}`, "false"},
1368                 {`{{or .Zero false}}`, "false"},
1369                 {`{{or (index .Slice 1) true}}`, "1"},
1370                 {`{{or .One true}}`, "1"},
1371                 {`{{not (index .Slice 0)}}`, "true"},
1372                 {`{{not .Zero}}`, "true"},
1373                 {`{{not (index .Slice 1)}}`, "false"},
1374                 {`{{not .One}}`, "false"},
1375                 {`{{eq (index .Slice 0) .Zero}}`, "true"},
1376                 {`{{eq (index .Slice 1) .One}}`, "true"},
1377                 {`{{ne (index .Slice 0) .Zero}}`, "false"},
1378                 {`{{ne (index .Slice 1) .One}}`, "false"},
1379                 {`{{ge (index .Slice 0) .One}}`, "false"},
1380                 {`{{ge (index .Slice 1) .Zero}}`, "true"},
1381                 {`{{gt (index .Slice 0) .One}}`, "false"},
1382                 {`{{gt (index .Slice 1) .Zero}}`, "true"},
1383                 {`{{le (index .Slice 0) .One}}`, "true"},
1384                 {`{{le (index .Slice 1) .Zero}}`, "false"},
1385                 {`{{lt (index .Slice 0) .One}}`, "true"},
1386                 {`{{lt (index .Slice 1) .Zero}}`, "false"},
1387         }
1388
1389         for _, tt := range tests {
1390                 tmpl := Must(New("tmpl").Parse(tt.text))
1391                 var buf bytes.Buffer
1392                 err := tmpl.Execute(&buf, map[string]interface{}{
1393                         "PlusOne": func(n int) int {
1394                                 return n + 1
1395                         },
1396                         "Slice": []int{0, 1, 2, 3},
1397                         "One":   1,
1398                         "Two":   2,
1399                         "Nil":   nil,
1400                         "Zero":  0,
1401                 })
1402                 if strings.HasPrefix(tt.out, "ERROR:") {
1403                         e := strings.TrimSpace(strings.TrimPrefix(tt.out, "ERROR:"))
1404                         if err == nil || !strings.Contains(err.Error(), e) {
1405                                 t.Errorf("%s: Execute: %v, want error %q", tt.text, err, e)
1406                         }
1407                         continue
1408                 }
1409                 if err != nil {
1410                         t.Errorf("%s: Execute: %v", tt.text, err)
1411                         continue
1412                 }
1413                 if buf.String() != tt.out {
1414                         t.Errorf("%s: template output = %q, want %q", tt.text, &buf, tt.out)
1415                 }
1416         }
1417 }