src/encoding/json/stream_test.go - go - Git at Google

 // Copyright 2010 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package json

 import (
 	"bytes"
 	"io"
 	"log"
 	"net"
 	"net/http"
 	"net/http/httptest"
 	"reflect"
 	"runtime/debug"
 	"strings"
 	"testing"
 )

 // Test values for the stream test.
 // One of each JSON kind.
 var streamTest = []any{
 	0.1,
 	"hello",
 	nil,
 	true,
 	false,
 	[]any{"a", "b", "c"},
 	map[string]any{"K": "Kelvin", "ß": "long s"},
 	3.14, // another value to make sure something can follow map
 }

 var streamEncoded = `0.1
 "hello"
 null
 true
 false
 ["a","b","c"]
 {"ß":"long s","K":"Kelvin"}
 3.14
 `

 func TestEncoder(t *testing.T) {
 	for i := 0; i <= len(streamTest); i++ {
 		var buf strings.Builder
 		enc := NewEncoder(&buf)
 		// Check that enc.SetIndent("", "") turns off indentation.
 		enc.SetIndent(">", ".")
 		enc.SetIndent("", "")
 		for j, v := range streamTest[0:i] {
 			if err := enc.Encode(v); err != nil {
 				t.Fatalf("encode #%d: %v", j, err)
 			}
 		}
 		if have, want := buf.String(), nlines(streamEncoded, i); have != want {
 			t.Errorf("encoding %d items: mismatch", i)
 			diff(t, []byte(have), []byte(want))
 			break
 		}
 	}
 }

 func TestEncoderErrorAndReuseEncodeState(t *testing.T) {
 	// Disable the GC temporarily to prevent encodeState's in Pool being cleaned away during the test.
 	percent := debug.SetGCPercent(-1)
 	defer debug.SetGCPercent(percent)

 	// Trigger an error in Marshal with cyclic data.
 	type Dummy struct {
 		Name string
 		Next *Dummy
 	}
 	dummy := Dummy{Name: "Dummy"}
 	dummy.Next = &dummy

 	var buf bytes.Buffer
 	enc := NewEncoder(&buf)
 	if err := enc.Encode(dummy); err == nil {
 		t.Errorf("Encode(dummy) == nil; want error")
 	}

 	type Data struct {
 		A string
 		I int
 	}
 	data := Data{A: "a", I: 1}
 	if err := enc.Encode(data); err != nil {
 		t.Errorf("Marshal(%v) = %v", data, err)
 	}

 	var data2 Data
 	if err := Unmarshal(buf.Bytes(), &data2); err != nil {
 		t.Errorf("Unmarshal(%v) = %v", data2, err)
 	}
 	if data2 != data {
 		t.Errorf("expect: %v, but get: %v", data, data2)
 	}
 }

 var streamEncodedIndent = `0.1
 "hello"
 null
 true
 false
 [
 >."a",
 >."b",
 >."c"
 >]
 {
 >."ß": "long s",
 >."K": "Kelvin"
 >}
 3.14
 `

 func TestEncoderIndent(t *testing.T) {
 	var buf strings.Builder
 	enc := NewEncoder(&buf)
 	enc.SetIndent(">", ".")
 	for _, v := range streamTest {
 		enc.Encode(v)
 	}
 	if have, want := buf.String(), streamEncodedIndent; have != want {
 		t.Error("indented encoding mismatch")
 		diff(t, []byte(have), []byte(want))
 	}
 }

 type strMarshaler string

 func (s strMarshaler) MarshalJSON() ([]byte, error) {
 	return []byte(s), nil
 }

 type strPtrMarshaler string

 func (s *strPtrMarshaler) MarshalJSON() ([]byte, error) {
 	return []byte(*s), nil
 }

 func TestEncoderSetEscapeHTML(t *testing.T) {
 	var c C
 	var ct CText
 	var tagStruct struct {
 		Valid   int `json:"<>&#! "`
 		Invalid int `json:"\\"`
 	}

 	// This case is particularly interesting, as we force the encoder to
 	// take the address of the Ptr field to use its MarshalJSON method. This
 	// is why the '&' is important.
 	marshalerStruct := &struct {
 		NonPtr strMarshaler
 		Ptr    strPtrMarshaler
 	}{`"<str>"`, `"<str>"`}

 	// https://golang.org/issue/34154
 	stringOption := struct {
 		Bar string `json:"bar,string"`
 	}{`<html>foobar</html>`}

 	for _, tt := range []struct {
 		name       string
 		v          any
 		wantEscape string
 		want       string
 	}{
 		{"c", c, `"\u003c\u0026\u003e"`, `"<&>"`},
 		{"ct", ct, `"\"\u003c\u0026\u003e\""`, `"\"<&>\""`},
 		{`"<&>"`, "<&>", `"\u003c\u0026\u003e"`, `"<&>"`},
 		{
 			"tagStruct", tagStruct,
 			`{"\u003c\u003e\u0026#! ":0,"Invalid":0}`,
 			`{"<>&#! ":0,"Invalid":0}`,
 		},
 		{
 			`"<str>"`, marshalerStruct,
 			`{"NonPtr":"\u003cstr\u003e","Ptr":"\u003cstr\u003e"}`,
 			`{"NonPtr":"<str>","Ptr":"<str>"}`,
 		},
 		{
 			"stringOption", stringOption,
 			`{"bar":"\"\\u003chtml\\u003efoobar\\u003c/html\\u003e\""}`,
 			`{"bar":"\"<html>foobar</html>\""}`,
 		},
 	} {
 		var buf strings.Builder
 		enc := NewEncoder(&buf)
 		if err := enc.Encode(tt.v); err != nil {
 			t.Errorf("Encode(%s): %s", tt.name, err)
 			continue
 		}
 		if got := strings.TrimSpace(buf.String()); got != tt.wantEscape {
 			t.Errorf("Encode(%s) = %#q, want %#q", tt.name, got, tt.wantEscape)
 		}
 		buf.Reset()
 		enc.SetEscapeHTML(false)
 		if err := enc.Encode(tt.v); err != nil {
 			t.Errorf("SetEscapeHTML(false) Encode(%s): %s", tt.name, err)
 			continue
 		}
 		if got := strings.TrimSpace(buf.String()); got != tt.want {
 			t.Errorf("SetEscapeHTML(false) Encode(%s) = %#q, want %#q",
 				tt.name, got, tt.want)
 		}
 	}
 }

 func TestDecoder(t *testing.T) {
 	for i := 0; i <= len(streamTest); i++ {
 		// Use stream without newlines as input,
 		// just to stress the decoder even more.
 		// Our test input does not include back-to-back numbers.
 		// Otherwise stripping the newlines would
 		// merge two adjacent JSON values.
 		var buf bytes.Buffer
 		for _, c := range nlines(streamEncoded, i) {
 			if c != '\n' {
 				buf.WriteRune(c)
 			}
 		}
 		out := make([]any, i)
 		dec := NewDecoder(&buf)
 		for j := range out {
 			if err := dec.Decode(&out[j]); err != nil {
 				t.Fatalf("decode #%d/%d: %v", j, i, err)
 			}
 		}
 		if !reflect.DeepEqual(out, streamTest[0:i]) {
 			t.Errorf("decoding %d items: mismatch", i)
 			for j := range out {
 				if !reflect.DeepEqual(out[j], streamTest[j]) {
 					t.Errorf("#%d: have %v want %v", j, out[j], streamTest[j])
 				}
 			}
 			break
 		}
 	}
 }

 func TestDecoderBuffered(t *testing.T) {
 	r := strings.NewReader(`{"Name": "Gopher"} extra `)
 	var m struct {
 		Name string
 	}
 	d := NewDecoder(r)
 	err := d.Decode(&m)
 	if err != nil {
 		t.Fatal(err)
 	}
 	if m.Name != "Gopher" {
 		t.Errorf("Name = %q; want Gopher", m.Name)
 	}
 	rest, err := io.ReadAll(d.Buffered())
 	if err != nil {
 		t.Fatal(err)
 	}
 	if g, w := string(rest), " extra "; g != w {
 		t.Errorf("Remaining = %q; want %q", g, w)
 	}
 }

 func nlines(s string, n int) string {
 	if n <= 0 {
 		return ""
 	}
 	for i, c := range s {
 		if c == '\n' {
 			if n--; n == 0 {
 				return s[0 : i+1]
 			}
 		}
 	}
 	return s
 }

 func TestRawMessage(t *testing.T) {
 	var data struct {
 		X  float64
 		Id RawMessage
 		Y  float32
 	}
 	const raw = `["\u0056",null]`
 	const msg = `{"X":0.1,"Id":["\u0056",null],"Y":0.2}`
 	err := Unmarshal([]byte(msg), &data)
 	if err != nil {
 		t.Fatalf("Unmarshal: %v", err)
 	}
 	if string([]byte(data.Id)) != raw {
 		t.Fatalf("Raw mismatch: have %#q want %#q", []byte(data.Id), raw)
 	}
 	b, err := Marshal(&data)
 	if err != nil {
 		t.Fatalf("Marshal: %v", err)
 	}
 	if string(b) != msg {
 		t.Fatalf("Marshal: have %#q want %#q", b, msg)
 	}
 }

 func TestNullRawMessage(t *testing.T) {
 	var data struct {
 		X     float64
 		Id    RawMessage
 		IdPtr *RawMessage
 		Y     float32
 	}
 	const msg = `{"X":0.1,"Id":null,"IdPtr":null,"Y":0.2}`
 	err := Unmarshal([]byte(msg), &data)
 	if err != nil {
 		t.Fatalf("Unmarshal: %v", err)
 	}
 	if want, got := "null", string(data.Id); want != got {
 		t.Fatalf("Raw mismatch: have %q, want %q", got, want)
 	}
 	if data.IdPtr != nil {
 		t.Fatalf("Raw pointer mismatch: have non-nil, want nil")
 	}
 	b, err := Marshal(&data)
 	if err != nil {
 		t.Fatalf("Marshal: %v", err)
 	}
 	if string(b) != msg {
 		t.Fatalf("Marshal: have %#q want %#q", b, msg)
 	}
 }

 var blockingTests = []string{
 	`{"x": 1}`,
 	`[1, 2, 3]`,
 }

 func TestBlocking(t *testing.T) {
 	for _, enc := range blockingTests {
 		r, w := net.Pipe()
 		go w.Write([]byte(enc))
 		var val any

 		// If Decode reads beyond what w.Write writes above,
 		// it will block, and the test will deadlock.
 		if err := NewDecoder(r).Decode(&val); err != nil {
 			t.Errorf("decoding %s: %v", enc, err)
 		}
 		r.Close()
 		w.Close()
 	}
 }

 type tokenStreamCase struct {
 	json      string
 	expTokens []any
 }

 type decodeThis struct {
 	v any
 }

 var tokenStreamCases = []tokenStreamCase{
 	// streaming token cases
 	{json: `10`, expTokens: []any{float64(10)}},
 	{json: ` [10] `, expTokens: []any{
 		Delim('['), float64(10), Delim(']')}},
 	{json: ` [false,10,"b"] `, expTokens: []any{
 		Delim('['), false, float64(10), "b", Delim(']')}},
 	{json: `{ "a": 1 }`, expTokens: []any{
 		Delim('{'), "a", float64(1), Delim('}')}},
 	{json: `{"a": 1, "b":"3"}`, expTokens: []any{
 		Delim('{'), "a", float64(1), "b", "3", Delim('}')}},
 	{json: ` [{"a": 1},{"a": 2}] `, expTokens: []any{
 		Delim('['),
 		Delim('{'), "a", float64(1), Delim('}'),
 		Delim('{'), "a", float64(2), Delim('}'),
 		Delim(']')}},
 	{json: `{"obj": {"a": 1}}`, expTokens: []any{
 		Delim('{'), "obj", Delim('{'), "a", float64(1), Delim('}'),
 		Delim('}')}},
 	{json: `{"obj": [{"a": 1}]}`, expTokens: []any{
 		Delim('{'), "obj", Delim('['),
 		Delim('{'), "a", float64(1), Delim('}'),
 		Delim(']'), Delim('}')}},

 	// streaming tokens with intermittent Decode()
 	{json: `{ "a": 1 }`, expTokens: []any{
 		Delim('{'), "a",
 		decodeThis{float64(1)},
 		Delim('}')}},
 	{json: ` [ { "a" : 1 } ] `, expTokens: []any{
 		Delim('['),
 		decodeThis{map[string]any{"a": float64(1)}},
 		Delim(']')}},
 	{json: ` [{"a": 1},{"a": 2}] `, expTokens: []any{
 		Delim('['),
 		decodeThis{map[string]any{"a": float64(1)}},
 		decodeThis{map[string]any{"a": float64(2)}},
 		Delim(']')}},
 	{json: `{ "obj" : [ { "a" : 1 } ] }`, expTokens: []any{
 		Delim('{'), "obj", Delim('['),
 		decodeThis{map[string]any{"a": float64(1)}},
 		Delim(']'), Delim('}')}},

 	{json: `{"obj": {"a": 1}}`, expTokens: []any{
 		Delim('{'), "obj",
 		decodeThis{map[string]any{"a": float64(1)}},
 		Delim('}')}},
 	{json: `{"obj": [{"a": 1}]}`, expTokens: []any{
 		Delim('{'), "obj",
 		decodeThis{[]any{
 			map[string]any{"a": float64(1)},
 		}},
 		Delim('}')}},
 	{json: ` [{"a": 1} {"a": 2}] `, expTokens: []any{
 		Delim('['),
 		decodeThis{map[string]any{"a": float64(1)}},
 		decodeThis{&SyntaxError{"expected comma after array element", 11}},
 	}},
 	{json: `{ "` + strings.Repeat("a", 513) + `" 1 }`, expTokens: []any{
 		Delim('{'), strings.Repeat("a", 513),
 		decodeThis{&SyntaxError{"expected colon after object key", 518}},
 	}},
 	{json: `{ "\a" }`, expTokens: []any{
 		Delim('{'),
 		&SyntaxError{"invalid character 'a' in string escape code", 3},
 	}},
 	{json: ` \a`, expTokens: []any{
 		&SyntaxError{"invalid character '\\\\' looking for beginning of value", 1},
 	}},
 }

 func TestDecodeInStream(t *testing.T) {
 	for ci, tcase := range tokenStreamCases {

 		dec := NewDecoder(strings.NewReader(tcase.json))
 		for i, etk := range tcase.expTokens {

 			var tk any
 			var err error

 			if dt, ok := etk.(decodeThis); ok {
 				etk = dt.v
 				err = dec.Decode(&tk)
 			} else {
 				tk, err = dec.Token()
 			}
 			if experr, ok := etk.(error); ok {
 				if err == nil || !reflect.DeepEqual(err, experr) {
 					t.Errorf("case %v: Expected error %#v in %q, but was %#v", ci, experr, tcase.json, err)
 				}
 				break
 			} else if err == io.EOF {
 				t.Errorf("case %v: Unexpected EOF in %q", ci, tcase.json)
 				break
 			} else if err != nil {
 				t.Errorf("case %v: Unexpected error '%#v' in %q", ci, err, tcase.json)
 				break
 			}
 			if !reflect.DeepEqual(tk, etk) {
 				t.Errorf(`case %v: %q @ %v expected %T(%v) was %T(%v)`, ci, tcase.json, i, etk, etk, tk, tk)
 				break
 			}
 		}
 	}
 }

 // Test from golang.org/issue/11893
 func TestHTTPDecoding(t *testing.T) {
 	const raw = `{ "foo": "bar" }`

 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Write([]byte(raw))
 	}))
 	defer ts.Close()
 	res, err := http.Get(ts.URL)
 	if err != nil {
 		log.Fatalf("GET failed: %v", err)
 	}
 	defer res.Body.Close()

 	foo := struct {
 		Foo string
 	}{}

 	d := NewDecoder(res.Body)
 	err = d.Decode(&foo)
 	if err != nil {
 		t.Fatalf("Decode: %v", err)
 	}
 	if foo.Foo != "bar" {
 		t.Errorf("decoded %q; want \"bar\"", foo.Foo)
 	}

 	// make sure we get the EOF the second time
 	err = d.Decode(&foo)
 	if err != io.EOF {
 		t.Errorf("err = %v; want io.EOF", err)
 	}
 }
	// Copyright 2010 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package json

	import (
	"bytes"
	"io"
	"log"
	"net"
	"net/http"
	"net/http/httptest"
	"reflect"
	"runtime/debug"
	"strings"
	"testing"
	)

	// Test values for the stream test.
	// One of each JSON kind.
	var streamTest = []any{
	0.1,
	"hello",
	nil,
	true,
	false,
	[]any{"a", "b", "c"},
	map[string]any{"K": "Kelvin", "ß": "long s"},
	3.14, // another value to make sure something can follow map
	}

	var streamEncoded = `0.1
	"hello"
	null
	true
	false
	["a","b","c"]
	{"ß":"long s","K":"Kelvin"}
	3.14
	`

	func TestEncoder(t *testing.T) {
	for i := 0; i <= len(streamTest); i++ {
	var buf strings.Builder
	enc := NewEncoder(&buf)
	// Check that enc.SetIndent("", "") turns off indentation.
	enc.SetIndent(">", ".")
	enc.SetIndent("", "")
	for j, v := range streamTest[0:i] {
	if err := enc.Encode(v); err != nil {
	t.Fatalf("encode #%d: %v", j, err)
	}
	}
	if have, want := buf.String(), nlines(streamEncoded, i); have != want {
	t.Errorf("encoding %d items: mismatch", i)
	diff(t, []byte(have), []byte(want))
	break
	}
	}
	}

	func TestEncoderErrorAndReuseEncodeState(t *testing.T) {
	// Disable the GC temporarily to prevent encodeState's in Pool being cleaned away during the test.
	percent := debug.SetGCPercent(-1)
	defer debug.SetGCPercent(percent)

	// Trigger an error in Marshal with cyclic data.
	type Dummy struct {
	Name string
	Next *Dummy
	}
	dummy := Dummy{Name: "Dummy"}
	dummy.Next = &dummy

	var buf bytes.Buffer
	enc := NewEncoder(&buf)
	if err := enc.Encode(dummy); err == nil {
	t.Errorf("Encode(dummy) == nil; want error")
	}

	type Data struct {
	A string
	I int
	}
	data := Data{A: "a", I: 1}
	if err := enc.Encode(data); err != nil {
	t.Errorf("Marshal(%v) = %v", data, err)
	}

	var data2 Data
	if err := Unmarshal(buf.Bytes(), &data2); err != nil {
	t.Errorf("Unmarshal(%v) = %v", data2, err)
	}
	if data2 != data {
	t.Errorf("expect: %v, but get: %v", data, data2)
	}
	}

	var streamEncodedIndent = `0.1
	"hello"
	null
	true
	false
	[
	>."a",
	>."b",
	>."c"
	>]
	{
	>."ß": "long s",
	>."K": "Kelvin"
	>}
	3.14
	`

	func TestEncoderIndent(t *testing.T) {
	var buf strings.Builder
	enc := NewEncoder(&buf)
	enc.SetIndent(">", ".")
	for _, v := range streamTest {
	enc.Encode(v)
	}
	if have, want := buf.String(), streamEncodedIndent; have != want {
	t.Error("indented encoding mismatch")
	diff(t, []byte(have), []byte(want))
	}
	}

	type strMarshaler string

	func (s strMarshaler) MarshalJSON() ([]byte, error) {
	return []byte(s), nil
	}

	type strPtrMarshaler string

	func (s *strPtrMarshaler) MarshalJSON() ([]byte, error) {
	return []byte(*s), nil
	}

	func TestEncoderSetEscapeHTML(t *testing.T) {
	var c C
	var ct CText
	var tagStruct struct {
	Valid int `json:"<>&#! "`
	Invalid int `json:"\\"`
	}

	// This case is particularly interesting, as we force the encoder to
	// take the address of the Ptr field to use its MarshalJSON method. This
	// is why the '&' is important.
	marshalerStruct := &struct {
	NonPtr strMarshaler
	Ptr strPtrMarshaler
	}{`"<str>"`, `"<str>"`}

	// https://golang.org/issue/34154
	stringOption := struct {
	Bar string `json:"bar,string"`
	}{`<html>foobar</html>`}

	for _, tt := range []struct {
	name string
	v any
	wantEscape string
	want string
	}{
	{"c", c, `"\u003c\u0026\u003e"`, `"<&>"`},
	{"ct", ct, `"\"\u003c\u0026\u003e\""`, `"\"<&>\""`},
	{`"<&>"`, "<&>", `"\u003c\u0026\u003e"`, `"<&>"`},
	{
	"tagStruct", tagStruct,
	`{"\u003c\u003e\u0026#! ":0,"Invalid":0}`,
	`{"<>&#! ":0,"Invalid":0}`,
	},
	{
	`"<str>"`, marshalerStruct,
	`{"NonPtr":"\u003cstr\u003e","Ptr":"\u003cstr\u003e"}`,
	`{"NonPtr":"<str>","Ptr":"<str>"}`,
	},
	{
	"stringOption", stringOption,
	`{"bar":"\"\\u003chtml\\u003efoobar\\u003c/html\\u003e\""}`,
	`{"bar":"\"<html>foobar</html>\""}`,
	},
	} {
	var buf strings.Builder
	enc := NewEncoder(&buf)
	if err := enc.Encode(tt.v); err != nil {
	t.Errorf("Encode(%s): %s", tt.name, err)
	continue
	}
	if got := strings.TrimSpace(buf.String()); got != tt.wantEscape {
	t.Errorf("Encode(%s) = %#q, want %#q", tt.name, got, tt.wantEscape)
	}
	buf.Reset()
	enc.SetEscapeHTML(false)
	if err := enc.Encode(tt.v); err != nil {
	t.Errorf("SetEscapeHTML(false) Encode(%s): %s", tt.name, err)
	continue
	}
	if got := strings.TrimSpace(buf.String()); got != tt.want {
	t.Errorf("SetEscapeHTML(false) Encode(%s) = %#q, want %#q",
	tt.name, got, tt.want)
	}
	}
	}

	func TestDecoder(t *testing.T) {
	for i := 0; i <= len(streamTest); i++ {
	// Use stream without newlines as input,
	// just to stress the decoder even more.
	// Our test input does not include back-to-back numbers.
	// Otherwise stripping the newlines would
	// merge two adjacent JSON values.
	var buf bytes.Buffer
	for _, c := range nlines(streamEncoded, i) {
	if c != '\n' {
	buf.WriteRune(c)
	}
	}
	out := make([]any, i)
	dec := NewDecoder(&buf)
	for j := range out {
	if err := dec.Decode(&out[j]); err != nil {
	t.Fatalf("decode #%d/%d: %v", j, i, err)
	}
	}
	if !reflect.DeepEqual(out, streamTest[0:i]) {
	t.Errorf("decoding %d items: mismatch", i)
	for j := range out {
	if !reflect.DeepEqual(out[j], streamTest[j]) {
	t.Errorf("#%d: have %v want %v", j, out[j], streamTest[j])
	}
	}
	break
	}
	}
	}

	func TestDecoderBuffered(t *testing.T) {
	r := strings.NewReader(`{"Name": "Gopher"} extra `)
	var m struct {
	Name string
	}
	d := NewDecoder(r)
	err := d.Decode(&m)
	if err != nil {
	t.Fatal(err)
	}
	if m.Name != "Gopher" {
	t.Errorf("Name = %q; want Gopher", m.Name)
	}
	rest, err := io.ReadAll(d.Buffered())
	if err != nil {
	t.Fatal(err)
	}
	if g, w := string(rest), " extra "; g != w {
	t.Errorf("Remaining = %q; want %q", g, w)
	}
	}

	func nlines(s string, n int) string {
	if n <= 0 {
	return ""
	}
	for i, c := range s {
	if c == '\n' {
	if n--; n == 0 {
	return s[0 : i+1]
	}
	}
	}
	return s
	}

	func TestRawMessage(t *testing.T) {
	var data struct {
	X float64
	Id RawMessage
	Y float32
	}
	const raw = `["\u0056",null]`
	const msg = `{"X":0.1,"Id":["\u0056",null],"Y":0.2}`
	err := Unmarshal([]byte(msg), &data)
	if err != nil {
	t.Fatalf("Unmarshal: %v", err)
	}
	if string([]byte(data.Id)) != raw {
	t.Fatalf("Raw mismatch: have %#q want %#q", []byte(data.Id), raw)
	}
	b, err := Marshal(&data)
	if err != nil {
	t.Fatalf("Marshal: %v", err)
	}
	if string(b) != msg {
	t.Fatalf("Marshal: have %#q want %#q", b, msg)
	}
	}

	func TestNullRawMessage(t *testing.T) {
	var data struct {
	X float64
	Id RawMessage
	IdPtr *RawMessage
	Y float32
	}
	const msg = `{"X":0.1,"Id":null,"IdPtr":null,"Y":0.2}`
	err := Unmarshal([]byte(msg), &data)
	if err != nil {
	t.Fatalf("Unmarshal: %v", err)
	}
	if want, got := "null", string(data.Id); want != got {
	t.Fatalf("Raw mismatch: have %q, want %q", got, want)
	}
	if data.IdPtr != nil {
	t.Fatalf("Raw pointer mismatch: have non-nil, want nil")
	}
	b, err := Marshal(&data)
	if err != nil {
	t.Fatalf("Marshal: %v", err)
	}
	if string(b) != msg {
	t.Fatalf("Marshal: have %#q want %#q", b, msg)
	}
	}

	var blockingTests = []string{
	`{"x": 1}`,
	`[1, 2, 3]`,
	}

	func TestBlocking(t *testing.T) {
	for _, enc := range blockingTests {
	r, w := net.Pipe()
	go w.Write([]byte(enc))
	var val any

	// If Decode reads beyond what w.Write writes above,
	// it will block, and the test will deadlock.
	if err := NewDecoder(r).Decode(&val); err != nil {
	t.Errorf("decoding %s: %v", enc, err)
	}
	r.Close()
	w.Close()
	}
	}

	type tokenStreamCase struct {
	json string
	expTokens []any
	}

	type decodeThis struct {
	v any
	}

	var tokenStreamCases = []tokenStreamCase{
	// streaming token cases
	{json: `10`, expTokens: []any{float64(10)}},
	{json: ` [10] `, expTokens: []any{
	Delim('['), float64(10), Delim(']')}},
	{json: ` [false,10,"b"] `, expTokens: []any{
	Delim('['), false, float64(10), "b", Delim(']')}},
	{json: `{ "a": 1 }`, expTokens: []any{
	Delim('{'), "a", float64(1), Delim('}')}},
	{json: `{"a": 1, "b":"3"}`, expTokens: []any{
	Delim('{'), "a", float64(1), "b", "3", Delim('}')}},
	{json: ` [{"a": 1},{"a": 2}] `, expTokens: []any{
	Delim('['),
	Delim('{'), "a", float64(1), Delim('}'),
	Delim('{'), "a", float64(2), Delim('}'),
	Delim(']')}},
	{json: `{"obj": {"a": 1}}`, expTokens: []any{
	Delim('{'), "obj", Delim('{'), "a", float64(1), Delim('}'),
	Delim('}')}},
	{json: `{"obj": [{"a": 1}]}`, expTokens: []any{
	Delim('{'), "obj", Delim('['),
	Delim('{'), "a", float64(1), Delim('}'),
	Delim(']'), Delim('}')}},

	// streaming tokens with intermittent Decode()
	{json: `{ "a": 1 }`, expTokens: []any{
	Delim('{'), "a",
	decodeThis{float64(1)},
	Delim('}')}},
	{json: ` [ { "a" : 1 } ] `, expTokens: []any{
	Delim('['),
	decodeThis{map[string]any{"a": float64(1)}},
	Delim(']')}},
	{json: ` [{"a": 1},{"a": 2}] `, expTokens: []any{
	Delim('['),
	decodeThis{map[string]any{"a": float64(1)}},
	decodeThis{map[string]any{"a": float64(2)}},
	Delim(']')}},
	{json: `{ "obj" : [ { "a" : 1 } ] }`, expTokens: []any{
	Delim('{'), "obj", Delim('['),
	decodeThis{map[string]any{"a": float64(1)}},
	Delim(']'), Delim('}')}},

	{json: `{"obj": {"a": 1}}`, expTokens: []any{
	Delim('{'), "obj",
	decodeThis{map[string]any{"a": float64(1)}},
	Delim('}')}},
	{json: `{"obj": [{"a": 1}]}`, expTokens: []any{
	Delim('{'), "obj",
	decodeThis{[]any{
	map[string]any{"a": float64(1)},
	}},
	Delim('}')}},
	{json: ` [{"a": 1} {"a": 2}] `, expTokens: []any{
	Delim('['),
	decodeThis{map[string]any{"a": float64(1)}},
	decodeThis{&SyntaxError{"expected comma after array element", 11}},
	}},
	{json: `{ "` + strings.Repeat("a", 513) + `" 1 }`, expTokens: []any{
	Delim('{'), strings.Repeat("a", 513),
	decodeThis{&SyntaxError{"expected colon after object key", 518}},
	}},
	{json: `{ "\a" }`, expTokens: []any{
	Delim('{'),
	&SyntaxError{"invalid character 'a' in string escape code", 3},
	}},
	{json: ` \a`, expTokens: []any{
	&SyntaxError{"invalid character '\\\\' looking for beginning of value", 1},
	}},
	}

	func TestDecodeInStream(t *testing.T) {
	for ci, tcase := range tokenStreamCases {

	dec := NewDecoder(strings.NewReader(tcase.json))
	for i, etk := range tcase.expTokens {

	var tk any
	var err error

	if dt, ok := etk.(decodeThis); ok {
	etk = dt.v
	err = dec.Decode(&tk)
	} else {
	tk, err = dec.Token()
	}
	if experr, ok := etk.(error); ok {
	if err == nil \|\| !reflect.DeepEqual(err, experr) {
	t.Errorf("case %v: Expected error %#v in %q, but was %#v", ci, experr, tcase.json, err)
	}
	break
	} else if err == io.EOF {
	t.Errorf("case %v: Unexpected EOF in %q", ci, tcase.json)
	break
	} else if err != nil {
	t.Errorf("case %v: Unexpected error '%#v' in %q", ci, err, tcase.json)
	break
	}
	if !reflect.DeepEqual(tk, etk) {
	t.Errorf(`case %v: %q @ %v expected %T(%v) was %T(%v)`, ci, tcase.json, i, etk, etk, tk, tk)
	break
	}
	}
	}
	}

	// Test from golang.org/issue/11893
	func TestHTTPDecoding(t *testing.T) {
	const raw = `{ "foo": "bar" }`

	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
	w.Write([]byte(raw))
	}))
	defer ts.Close()
	res, err := http.Get(ts.URL)
	if err != nil {
	log.Fatalf("GET failed: %v", err)
	}
	defer res.Body.Close()

	foo := struct {
	Foo string
	}{}

	d := NewDecoder(res.Body)
	err = d.Decode(&foo)
	if err != nil {
	t.Fatalf("Decode: %v", err)
	}
	if foo.Foo != "bar" {
	t.Errorf("decoded %q; want \"bar\"", foo.Foo)
	}

	// make sure we get the EOF the second time
	err = d.Decode(&foo)
	if err != io.EOF {
	t.Errorf("err = %v; want io.EOF", err)
	}
	}