src/pkg/gob/encoder_test.go - go - Git at Google

 // Copyright 2009 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 gob

 import (
 	"bytes"
 	"fmt"
 	"io"
 	"os"
 	"reflect"
 	"strings"
 	"testing"
 )

 type ET2 struct {
 	X string
 }

 type ET1 struct {
 	A    int
 	Et2  *ET2
 	Next *ET1
 }

 // Like ET1 but with a different name for a field
 type ET3 struct {
 	A             int
 	Et2           *ET2
 	DifferentNext *ET1
 }

 // Like ET1 but with a different type for a field
 type ET4 struct {
 	A    int
 	Et2  float64
 	Next int
 }

 func TestEncoderDecoder(t *testing.T) {
 	b := new(bytes.Buffer)
 	enc := NewEncoder(b)
 	et1 := new(ET1)
 	et1.A = 7
 	et1.Et2 = new(ET2)
 	err := enc.Encode(et1)
 	if err != nil {
 		t.Error("encoder fail:", err)
 	}
 	dec := NewDecoder(b)
 	newEt1 := new(ET1)
 	err = dec.Decode(newEt1)
 	if err != nil {
 		t.Fatal("error decoding ET1:", err)
 	}

 	if !reflect.DeepEqual(et1, newEt1) {
 		t.Fatalf("invalid data for et1: expected %+v; got %+v", *et1, *newEt1)
 	}
 	if b.Len() != 0 {
 		t.Error("not at eof;", b.Len(), "bytes left")
 	}

 	enc.Encode(et1)
 	newEt1 = new(ET1)
 	err = dec.Decode(newEt1)
 	if err != nil {
 		t.Fatal("round 2: error decoding ET1:", err)
 	}
 	if !reflect.DeepEqual(et1, newEt1) {
 		t.Fatalf("round 2: invalid data for et1: expected %+v; got %+v", *et1, *newEt1)
 	}
 	if b.Len() != 0 {
 		t.Error("round 2: not at eof;", b.Len(), "bytes left")
 	}

 	// Now test with a running encoder/decoder pair that we recognize a type mismatch.
 	err = enc.Encode(et1)
 	if err != nil {
 		t.Error("round 3: encoder fail:", err)
 	}
 	newEt2 := new(ET2)
 	err = dec.Decode(newEt2)
 	if err == nil {
 		t.Fatal("round 3: expected `bad type' error decoding ET2")
 	}
 }

 // Run one value through the encoder/decoder, but use the wrong type.
 // Input is always an ET1; we compare it to whatever is under 'e'.
 func badTypeCheck(e interface{}, shouldFail bool, msg string, t *testing.T) {
 	b := new(bytes.Buffer)
 	enc := NewEncoder(b)
 	et1 := new(ET1)
 	et1.A = 7
 	et1.Et2 = new(ET2)
 	err := enc.Encode(et1)
 	if err != nil {
 		t.Error("encoder fail:", err)
 	}
 	dec := NewDecoder(b)
 	err = dec.Decode(e)
 	if shouldFail && err == nil {
 		t.Error("expected error for", msg)
 	}
 	if !shouldFail && err != nil {
 		t.Error("unexpected error for", msg, err)
 	}
 }

 // Test that we recognize a bad type the first time.
 func TestWrongTypeDecoder(t *testing.T) {
 	badTypeCheck(new(ET2), true, "no fields in common", t)
 	badTypeCheck(new(ET3), false, "different name of field", t)
 	badTypeCheck(new(ET4), true, "different type of field", t)
 }

 func corruptDataCheck(s string, err os.Error, t *testing.T) {
 	b := bytes.NewBufferString(s)
 	dec := NewDecoder(b)
 	err1 := dec.Decode(new(ET2))
 	if err1 != err {
 		t.Errorf("from %q expected error %s; got %s", s, err, err1)
 	}
 }

 // Check that we survive bad data.
 func TestBadData(t *testing.T) {
 	corruptDataCheck("", os.EOF, t)
 	corruptDataCheck("\x7Fhi", io.ErrUnexpectedEOF, t)
 	corruptDataCheck("\x03now is the time for all good men", errBadType, t)
 }

 // Types not supported by the Encoder.
 var unsupportedValues = []interface{}{
 	make(chan int),
 	func(a int) bool { return true },
 }

 func TestUnsupported(t *testing.T) {
 	var b bytes.Buffer
 	enc := NewEncoder(&b)
 	for _, v := range unsupportedValues {
 		err := enc.Encode(v)
 		if err == nil {
 			t.Errorf("expected error for %T; got none", v)
 		}
 	}
 }

 func encAndDec(in, out interface{}) os.Error {
 	b := new(bytes.Buffer)
 	enc := NewEncoder(b)
 	err := enc.Encode(in)
 	if err != nil {
 		return err
 	}
 	dec := NewDecoder(b)
 	err = dec.Decode(out)
 	if err != nil {
 		return err
 	}
 	return nil
 }

 func TestTypeToPtrType(t *testing.T) {
 	// Encode a T, decode a *T
 	type Type0 struct {
 		A int
 	}
 	t0 := Type0{7}
 	t0p := (*Type0)(nil)
 	if err := encAndDec(t0, t0p); err != nil {
 		t.Error(err)
 	}
 }

 func TestPtrTypeToType(t *testing.T) {
 	// Encode a *T, decode a T
 	type Type1 struct {
 		A uint
 	}
 	t1p := &Type1{17}
 	var t1 Type1
 	if err := encAndDec(t1, t1p); err != nil {
 		t.Error(err)
 	}
 }

 func TestTypeToPtrPtrPtrPtrType(t *testing.T) {
 	type Type2 struct {
 		A ****float64
 	}
 	t2 := Type2{}
 	t2.A = new(***float64)
 	*t2.A = new(**float64)
 	**t2.A = new(*float64)
 	***t2.A = new(float64)
 	****t2.A = 27.4
 	t2pppp := new(***Type2)
 	if err := encAndDec(t2, t2pppp); err != nil {
 		t.Fatal(err)
 	}
 	if ****(****t2pppp).A != ****t2.A {
 		t.Errorf("wrong value after decode: %g not %g", ****(****t2pppp).A, ****t2.A)
 	}
 }

 func TestSlice(t *testing.T) {
 	type Type3 struct {
 		A []string
 	}
 	t3p := &Type3{[]string{"hello", "world"}}
 	var t3 Type3
 	if err := encAndDec(t3, t3p); err != nil {
 		t.Error(err)
 	}
 }

 func TestValueError(t *testing.T) {
 	// Encode a *T, decode a T
 	type Type4 struct {
 		A int
 	}
 	t4p := &Type4{3}
 	var t4 Type4 // note: not a pointer.
 	if err := encAndDec(t4p, t4); err == nil || strings.Index(err.String(), "pointer") < 0 {
 		t.Error("expected error about pointer; got", err)
 	}
 }

 func TestArray(t *testing.T) {
 	type Type5 struct {
 		A [3]string
 		B [3]byte
 	}
 	type Type6 struct {
 		A [2]string // can't hold t5.a
 	}
 	t5 := Type5{[3]string{"hello", ",", "world"}, [3]byte{1, 2, 3}}
 	var t5p Type5
 	if err := encAndDec(t5, &t5p); err != nil {
 		t.Error(err)
 	}
 	var t6 Type6
 	if err := encAndDec(t5, &t6); err == nil {
 		t.Error("should fail with mismatched array sizes")
 	}
 }

 func TestRecursiveMapType(t *testing.T) {
 	type recursiveMap map[string]recursiveMap
 	r1 := recursiveMap{"A": recursiveMap{"B": nil, "C": nil}, "D": nil}
 	r2 := make(recursiveMap)
 	if err := encAndDec(r1, &r2); err != nil {
 		t.Error(err)
 	}
 }

 func TestRecursiveSliceType(t *testing.T) {
 	type recursiveSlice []recursiveSlice
 	r1 := recursiveSlice{0: recursiveSlice{0: nil}, 1: nil}
 	r2 := make(recursiveSlice, 0)
 	if err := encAndDec(r1, &r2); err != nil {
 		t.Error(err)
 	}
 }

 // Regression test for bug: must send zero values inside arrays
 func TestDefaultsInArray(t *testing.T) {
 	type Type7 struct {
 		B []bool
 		I []int
 		S []string
 		F []float64
 	}
 	t7 := Type7{
 		[]bool{false, false, true},
 		[]int{0, 0, 1},
 		[]string{"hi", "", "there"},
 		[]float64{0, 0, 1},
 	}
 	var t7p Type7
 	if err := encAndDec(t7, &t7p); err != nil {
 		t.Error(err)
 	}
 }

 var testInt int
 var testFloat32 float32
 var testString string
 var testSlice []string
 var testMap map[string]int
 var testArray [7]int

 type SingleTest struct {
 	in  interface{}
 	out interface{}
 	err string
 }

 var singleTests = []SingleTest{
 	{17, &testInt, ""},
 	{float32(17.5), &testFloat32, ""},
 	{"bike shed", &testString, ""},
 	{[]string{"bike", "shed", "paint", "color"}, &testSlice, ""},
 	{map[string]int{"seven": 7, "twelve": 12}, &testMap, ""},
 	{[7]int{4, 55, 0, 0, 0, 0, 0}, &testArray, ""}, // case that once triggered a bug
 	{[7]int{4, 55, 1, 44, 22, 66, 1234}, &testArray, ""},

 	// Decode errors
 	{172, &testFloat32, "wrong type"},
 }

 func TestSingletons(t *testing.T) {
 	b := new(bytes.Buffer)
 	enc := NewEncoder(b)
 	dec := NewDecoder(b)
 	for _, test := range singleTests {
 		b.Reset()
 		err := enc.Encode(test.in)
 		if err != nil {
 			t.Errorf("error encoding %v: %s", test.in, err)
 			continue
 		}
 		err = dec.Decode(test.out)
 		switch {
 		case err != nil && test.err == "":
 			t.Errorf("error decoding %v: %s", test.in, err)
 			continue
 		case err == nil && test.err != "":
 			t.Errorf("expected error decoding %v: %s", test.in, test.err)
 			continue
 		case err != nil && test.err != "":
 			if strings.Index(err.String(), test.err) < 0 {
 				t.Errorf("wrong error decoding %v: wanted %s, got %v", test.in, test.err, err)
 			}
 			continue
 		}
 		// Get rid of the pointer in the rhs
 		val := reflect.NewValue(test.out).(*reflect.PtrValue).Elem().Interface()
 		if !reflect.DeepEqual(test.in, val) {
 			t.Errorf("decoding singleton: expected %v got %v", test.in, val)
 		}
 	}
 }

 func TestStructNonStruct(t *testing.T) {
 	type Struct struct {
 		A string
 	}
 	type NonStruct string
 	s := Struct{"hello"}
 	var sp Struct
 	if err := encAndDec(s, &sp); err != nil {
 		t.Error(err)
 	}
 	var ns NonStruct
 	if err := encAndDec(s, &ns); err == nil {
 		t.Error("should get error for struct/non-struct")
 	} else if strings.Index(err.String(), "type") < 0 {
 		t.Error("for struct/non-struct expected type error; got", err)
 	}
 	// Now try the other way
 	var nsp NonStruct
 	if err := encAndDec(ns, &nsp); err != nil {
 		t.Error(err)
 	}
 	if err := encAndDec(ns, &s); err == nil {
 		t.Error("should get error for non-struct/struct")
 	} else if strings.Index(err.String(), "type") < 0 {
 		t.Error("for non-struct/struct expected type error; got", err)
 	}
 }

 type interfaceIndirectTestI interface {
 	F() bool
 }

 type interfaceIndirectTestT struct{}

 func (this *interfaceIndirectTestT) F() bool {
 	return true
 }

 // A version of a bug reported on golang-nuts.  Also tests top-level
 // slice of interfaces.  The issue was registering *T caused T to be
 // stored as the concrete type.
 func TestInterfaceIndirect(t *testing.T) {
 	Register(&interfaceIndirectTestT{})
 	b := new(bytes.Buffer)
 	w := []interfaceIndirectTestI{&interfaceIndirectTestT{}}
 	err := NewEncoder(b).Encode(w)
 	if err != nil {
 		t.Fatal("encode error:", err)
 	}

 	var r []interfaceIndirectTestI
 	err = NewDecoder(b).Decode(&r)
 	if err != nil {
 		t.Fatal("decode error:", err)
 	}
 }

 // Now follow various tests that decode into things that can't represent the
 // encoded value, all of which should be legal.

 // Also, when the ignored object contains an interface value, it may define
 // types. Make sure that skipping the value still defines the types by using
 // the encoder/decoder pair to send a value afterwards.  If an interface
 // is sent, its type in the test is always NewType0, so this checks that the
 // encoder and decoder don't skew with respect to type definitions.

 type Struct0 struct {
 	I interface{}
 }

 type NewType0 struct {
 	S string
 }

 type ignoreTest struct {
 	in, out interface{}
 }

 var ignoreTests = []ignoreTest{
 	// Decode normal struct into an empty struct
 	{&struct{ A int }{23}, &struct{}{}},
 	// Decode normal struct into a nil.
 	{&struct{ A int }{23}, nil},
 	// Decode singleton string into a nil.
 	{"hello, world", nil},
 	// Decode singleton slice into a nil.
 	{[]int{1, 2, 3, 4}, nil},
 	// Decode struct containing an interface into a nil.
 	{&Struct0{&NewType0{"value0"}}, nil},
 	// Decode singleton slice of interfaces into a nil.
 	{[]interface{}{"hi", &NewType0{"value1"}, 23}, nil},
 }

 func TestDecodeIntoNothing(t *testing.T) {
 	Register(new(NewType0))
 	for i, test := range ignoreTests {
 		b := new(bytes.Buffer)
 		enc := NewEncoder(b)
 		err := enc.Encode(test.in)
 		if err != nil {
 			t.Errorf("%d: encode error %s:", i, err)
 			continue
 		}
 		dec := NewDecoder(b)
 		err = dec.Decode(test.out)
 		if err != nil {
 			t.Errorf("%d: decode error: %s", i, err)
 			continue
 		}
 		// Now see if the encoder and decoder are in a consistent state.
 		str := fmt.Sprintf("Value %d", i)
 		err = enc.Encode(&NewType0{str})
 		if err != nil {
 			t.Fatalf("%d: NewType0 encode error: %s", i, err)
 		}
 		ns := new(NewType0)
 		err = dec.Decode(ns)
 		if err != nil {
 			t.Fatalf("%d: NewType0 decode error: %s", i, err)
 		}
 		if ns.S != str {
 			t.Fatalf("%d: expected %q got %q", i, str, ns.S)
 		}
 	}
 }

 // Another bug from golang-nuts, involving nested interfaces.
 type Bug0Outer struct {
 	Bug0Field interface{}
 }

 type Bug0Inner struct {
 	A int
 }

 func TestNestedInterfaces(t *testing.T) {
 	var buf bytes.Buffer
 	e := NewEncoder(&buf)
 	d := NewDecoder(&buf)
 	Register(new(Bug0Outer))
 	Register(new(Bug0Inner))
 	f := &Bug0Outer{&Bug0Outer{&Bug0Inner{7}}}
 	var v interface{} = f
 	err := e.Encode(&v)
 	if err != nil {
 		t.Fatal("Encode:", err)
 	}
 	err = d.Decode(&v)
 	if err != nil {
 		t.Fatal("Decode:", err)
 	}
 	// Make sure it decoded correctly.
 	outer1, ok := v.(*Bug0Outer)
 	if !ok {
 		t.Fatalf("v not Bug0Outer: %T", v)
 	}
 	outer2, ok := outer1.Bug0Field.(*Bug0Outer)
 	if !ok {
 		t.Fatalf("v.Bug0Field not Bug0Outer: %T", outer1.Bug0Field)
 	}
 	inner, ok := outer2.Bug0Field.(*Bug0Inner)
 	if !ok {
 		t.Fatalf("v.Bug0Field.Bug0Field not Bug0Inner: %T", outer2.Bug0Field)
 	}
 	if inner.A != 7 {
 		t.Fatalf("final value %d; expected %d", inner.A, 7)
 	}
 }
	// Copyright 2009 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 gob

	import (
	"bytes"
	"fmt"
	"io"
	"os"
	"reflect"
	"strings"
	"testing"
	)

	type ET2 struct {
	X string
	}

	type ET1 struct {
	A int
	Et2 *ET2
	Next *ET1
	}

	// Like ET1 but with a different name for a field
	type ET3 struct {
	A int
	Et2 *ET2
	DifferentNext *ET1
	}

	// Like ET1 but with a different type for a field
	type ET4 struct {
	A int
	Et2 float64
	Next int
	}

	func TestEncoderDecoder(t *testing.T) {
	b := new(bytes.Buffer)
	enc := NewEncoder(b)
	et1 := new(ET1)
	et1.A = 7
	et1.Et2 = new(ET2)
	err := enc.Encode(et1)
	if err != nil {
	t.Error("encoder fail:", err)
	}
	dec := NewDecoder(b)
	newEt1 := new(ET1)
	err = dec.Decode(newEt1)
	if err != nil {
	t.Fatal("error decoding ET1:", err)
	}

	if !reflect.DeepEqual(et1, newEt1) {
	t.Fatalf("invalid data for et1: expected %+v; got %+v", et1, newEt1)
	}
	if b.Len() != 0 {
	t.Error("not at eof;", b.Len(), "bytes left")
	}

	enc.Encode(et1)
	newEt1 = new(ET1)
	err = dec.Decode(newEt1)
	if err != nil {
	t.Fatal("round 2: error decoding ET1:", err)
	}
	if !reflect.DeepEqual(et1, newEt1) {
	t.Fatalf("round 2: invalid data for et1: expected %+v; got %+v", et1, newEt1)
	}
	if b.Len() != 0 {
	t.Error("round 2: not at eof;", b.Len(), "bytes left")
	}

	// Now test with a running encoder/decoder pair that we recognize a type mismatch.
	err = enc.Encode(et1)
	if err != nil {
	t.Error("round 3: encoder fail:", err)
	}
	newEt2 := new(ET2)
	err = dec.Decode(newEt2)
	if err == nil {
	t.Fatal("round 3: expected `bad type' error decoding ET2")
	}
	}

	// Run one value through the encoder/decoder, but use the wrong type.
	// Input is always an ET1; we compare it to whatever is under 'e'.
	func badTypeCheck(e interface{}, shouldFail bool, msg string, t *testing.T) {
	b := new(bytes.Buffer)
	enc := NewEncoder(b)
	et1 := new(ET1)
	et1.A = 7
	et1.Et2 = new(ET2)
	err := enc.Encode(et1)
	if err != nil {
	t.Error("encoder fail:", err)
	}
	dec := NewDecoder(b)
	err = dec.Decode(e)
	if shouldFail && err == nil {
	t.Error("expected error for", msg)
	}
	if !shouldFail && err != nil {
	t.Error("unexpected error for", msg, err)
	}
	}

	// Test that we recognize a bad type the first time.
	func TestWrongTypeDecoder(t *testing.T) {
	badTypeCheck(new(ET2), true, "no fields in common", t)
	badTypeCheck(new(ET3), false, "different name of field", t)
	badTypeCheck(new(ET4), true, "different type of field", t)
	}

	func corruptDataCheck(s string, err os.Error, t *testing.T) {
	b := bytes.NewBufferString(s)
	dec := NewDecoder(b)
	err1 := dec.Decode(new(ET2))
	if err1 != err {
	t.Errorf("from %q expected error %s; got %s", s, err, err1)
	}
	}

	// Check that we survive bad data.
	func TestBadData(t *testing.T) {
	corruptDataCheck("", os.EOF, t)
	corruptDataCheck("\x7Fhi", io.ErrUnexpectedEOF, t)
	corruptDataCheck("\x03now is the time for all good men", errBadType, t)
	}

	// Types not supported by the Encoder.
	var unsupportedValues = []interface{}{
	make(chan int),
	func(a int) bool { return true },
	}

	func TestUnsupported(t *testing.T) {
	var b bytes.Buffer
	enc := NewEncoder(&b)
	for _, v := range unsupportedValues {
	err := enc.Encode(v)
	if err == nil {
	t.Errorf("expected error for %T; got none", v)
	}
	}
	}

	func encAndDec(in, out interface{}) os.Error {
	b := new(bytes.Buffer)
	enc := NewEncoder(b)
	err := enc.Encode(in)
	if err != nil {
	return err
	}
	dec := NewDecoder(b)
	err = dec.Decode(out)
	if err != nil {
	return err
	}
	return nil
	}

	func TestTypeToPtrType(t *testing.T) {
	// Encode a T, decode a *T
	type Type0 struct {
	A int
	}
	t0 := Type0{7}
	t0p := (*Type0)(nil)
	if err := encAndDec(t0, t0p); err != nil {
	t.Error(err)
	}
	}

	func TestPtrTypeToType(t *testing.T) {
	// Encode a *T, decode a T
	type Type1 struct {
	A uint
	}
	t1p := &Type1{17}
	var t1 Type1
	if err := encAndDec(t1, t1p); err != nil {
	t.Error(err)
	}
	}

	func TestTypeToPtrPtrPtrPtrType(t *testing.T) {
	type Type2 struct {
	A ****float64
	}
	t2 := Type2{}
	t2.A = new(***float64)
	t2.A = new(*float64)
	*t2.A = new(float64)
	***t2.A = new(float64)
	****t2.A = 27.4
	t2pppp := new(***Type2)
	if err := encAndDec(t2, t2pppp); err != nil {
	t.Fatal(err)
	}
	if **(t2pppp).A != **t2.A {
	t.Errorf("wrong value after decode: %g not %g", **(t2pppp).A, **t2.A)
	}
	}

	func TestSlice(t *testing.T) {
	type Type3 struct {
	A []string
	}
	t3p := &Type3{[]string{"hello", "world"}}
	var t3 Type3
	if err := encAndDec(t3, t3p); err != nil {
	t.Error(err)
	}
	}

	func TestValueError(t *testing.T) {
	// Encode a *T, decode a T
	type Type4 struct {
	A int
	}
	t4p := &Type4{3}
	var t4 Type4 // note: not a pointer.
	if err := encAndDec(t4p, t4); err == nil \|\| strings.Index(err.String(), "pointer") < 0 {
	t.Error("expected error about pointer; got", err)
	}
	}

	func TestArray(t *testing.T) {
	type Type5 struct {
	A [3]string
	B [3]byte
	}
	type Type6 struct {
	A [2]string // can't hold t5.a
	}
	t5 := Type5{[3]string{"hello", ",", "world"}, [3]byte{1, 2, 3}}
	var t5p Type5
	if err := encAndDec(t5, &t5p); err != nil {
	t.Error(err)
	}
	var t6 Type6
	if err := encAndDec(t5, &t6); err == nil {
	t.Error("should fail with mismatched array sizes")
	}
	}

	func TestRecursiveMapType(t *testing.T) {
	type recursiveMap map[string]recursiveMap
	r1 := recursiveMap{"A": recursiveMap{"B": nil, "C": nil}, "D": nil}
	r2 := make(recursiveMap)
	if err := encAndDec(r1, &r2); err != nil {
	t.Error(err)
	}
	}

	func TestRecursiveSliceType(t *testing.T) {
	type recursiveSlice []recursiveSlice
	r1 := recursiveSlice{0: recursiveSlice{0: nil}, 1: nil}
	r2 := make(recursiveSlice, 0)
	if err := encAndDec(r1, &r2); err != nil {
	t.Error(err)
	}
	}

	// Regression test for bug: must send zero values inside arrays
	func TestDefaultsInArray(t *testing.T) {
	type Type7 struct {
	B []bool
	I []int
	S []string
	F []float64
	}
	t7 := Type7{
	[]bool{false, false, true},
	[]int{0, 0, 1},
	[]string{"hi", "", "there"},
	[]float64{0, 0, 1},
	}
	var t7p Type7
	if err := encAndDec(t7, &t7p); err != nil {
	t.Error(err)
	}
	}

	var testInt int
	var testFloat32 float32
	var testString string
	var testSlice []string
	var testMap map[string]int
	var testArray [7]int

	type SingleTest struct {
	in interface{}
	out interface{}
	err string
	}

	var singleTests = []SingleTest{
	{17, &testInt, ""},
	{float32(17.5), &testFloat32, ""},
	{"bike shed", &testString, ""},
	{[]string{"bike", "shed", "paint", "color"}, &testSlice, ""},
	{map[string]int{"seven": 7, "twelve": 12}, &testMap, ""},
	{[7]int{4, 55, 0, 0, 0, 0, 0}, &testArray, ""}, // case that once triggered a bug
	{[7]int{4, 55, 1, 44, 22, 66, 1234}, &testArray, ""},

	// Decode errors
	{172, &testFloat32, "wrong type"},
	}

	func TestSingletons(t *testing.T) {
	b := new(bytes.Buffer)
	enc := NewEncoder(b)
	dec := NewDecoder(b)
	for _, test := range singleTests {
	b.Reset()
	err := enc.Encode(test.in)
	if err != nil {
	t.Errorf("error encoding %v: %s", test.in, err)
	continue
	}
	err = dec.Decode(test.out)
	switch {
	case err != nil && test.err == "":
	t.Errorf("error decoding %v: %s", test.in, err)
	continue
	case err == nil && test.err != "":
	t.Errorf("expected error decoding %v: %s", test.in, test.err)
	continue
	case err != nil && test.err != "":
	if strings.Index(err.String(), test.err) < 0 {
	t.Errorf("wrong error decoding %v: wanted %s, got %v", test.in, test.err, err)
	}
	continue
	}
	// Get rid of the pointer in the rhs
	val := reflect.NewValue(test.out).(*reflect.PtrValue).Elem().Interface()
	if !reflect.DeepEqual(test.in, val) {
	t.Errorf("decoding singleton: expected %v got %v", test.in, val)
	}
	}
	}

	func TestStructNonStruct(t *testing.T) {
	type Struct struct {
	A string
	}
	type NonStruct string
	s := Struct{"hello"}
	var sp Struct
	if err := encAndDec(s, &sp); err != nil {
	t.Error(err)
	}
	var ns NonStruct
	if err := encAndDec(s, &ns); err == nil {
	t.Error("should get error for struct/non-struct")
	} else if strings.Index(err.String(), "type") < 0 {
	t.Error("for struct/non-struct expected type error; got", err)
	}
	// Now try the other way
	var nsp NonStruct
	if err := encAndDec(ns, &nsp); err != nil {
	t.Error(err)
	}
	if err := encAndDec(ns, &s); err == nil {
	t.Error("should get error for non-struct/struct")
	} else if strings.Index(err.String(), "type") < 0 {
	t.Error("for non-struct/struct expected type error; got", err)
	}
	}

	type interfaceIndirectTestI interface {
	F() bool
	}

	type interfaceIndirectTestT struct{}

	func (this *interfaceIndirectTestT) F() bool {
	return true
	}

	// A version of a bug reported on golang-nuts. Also tests top-level
	// slice of interfaces. The issue was registering *T caused T to be
	// stored as the concrete type.
	func TestInterfaceIndirect(t *testing.T) {
	Register(&interfaceIndirectTestT{})
	b := new(bytes.Buffer)
	w := []interfaceIndirectTestI{&interfaceIndirectTestT{}}
	err := NewEncoder(b).Encode(w)
	if err != nil {
	t.Fatal("encode error:", err)
	}

	var r []interfaceIndirectTestI
	err = NewDecoder(b).Decode(&r)
	if err != nil {
	t.Fatal("decode error:", err)
	}
	}

	// Now follow various tests that decode into things that can't represent the
	// encoded value, all of which should be legal.

	// Also, when the ignored object contains an interface value, it may define
	// types. Make sure that skipping the value still defines the types by using
	// the encoder/decoder pair to send a value afterwards. If an interface
	// is sent, its type in the test is always NewType0, so this checks that the
	// encoder and decoder don't skew with respect to type definitions.

	type Struct0 struct {
	I interface{}
	}

	type NewType0 struct {
	S string
	}

	type ignoreTest struct {
	in, out interface{}
	}

	var ignoreTests = []ignoreTest{
	// Decode normal struct into an empty struct
	{&struct{ A int }{23}, &struct{}{}},
	// Decode normal struct into a nil.
	{&struct{ A int }{23}, nil},
	// Decode singleton string into a nil.
	{"hello, world", nil},
	// Decode singleton slice into a nil.
	{[]int{1, 2, 3, 4}, nil},
	// Decode struct containing an interface into a nil.
	{&Struct0{&NewType0{"value0"}}, nil},
	// Decode singleton slice of interfaces into a nil.
	{[]interface{}{"hi", &NewType0{"value1"}, 23}, nil},
	}

	func TestDecodeIntoNothing(t *testing.T) {
	Register(new(NewType0))
	for i, test := range ignoreTests {
	b := new(bytes.Buffer)
	enc := NewEncoder(b)
	err := enc.Encode(test.in)
	if err != nil {
	t.Errorf("%d: encode error %s:", i, err)
	continue
	}
	dec := NewDecoder(b)
	err = dec.Decode(test.out)
	if err != nil {
	t.Errorf("%d: decode error: %s", i, err)
	continue
	}
	// Now see if the encoder and decoder are in a consistent state.
	str := fmt.Sprintf("Value %d", i)
	err = enc.Encode(&NewType0{str})
	if err != nil {
	t.Fatalf("%d: NewType0 encode error: %s", i, err)
	}
	ns := new(NewType0)
	err = dec.Decode(ns)
	if err != nil {
	t.Fatalf("%d: NewType0 decode error: %s", i, err)
	}
	if ns.S != str {
	t.Fatalf("%d: expected %q got %q", i, str, ns.S)
	}
	}
	}

	// Another bug from golang-nuts, involving nested interfaces.
	type Bug0Outer struct {
	Bug0Field interface{}
	}

	type Bug0Inner struct {
	A int
	}

	func TestNestedInterfaces(t *testing.T) {
	var buf bytes.Buffer
	e := NewEncoder(&buf)
	d := NewDecoder(&buf)
	Register(new(Bug0Outer))
	Register(new(Bug0Inner))
	f := &Bug0Outer{&Bug0Outer{&Bug0Inner{7}}}
	var v interface{} = f
	err := e.Encode(&v)
	if err != nil {
	t.Fatal("Encode:", err)
	}
	err = d.Decode(&v)
	if err != nil {
	t.Fatal("Decode:", err)
	}
	// Make sure it decoded correctly.
	outer1, ok := v.(*Bug0Outer)
	if !ok {
	t.Fatalf("v not Bug0Outer: %T", v)
	}
	outer2, ok := outer1.Bug0Field.(*Bug0Outer)
	if !ok {
	t.Fatalf("v.Bug0Field not Bug0Outer: %T", outer1.Bug0Field)
	}
	inner, ok := outer2.Bug0Field.(*Bug0Inner)
	if !ok {
	t.Fatalf("v.Bug0Field.Bug0Field not Bug0Inner: %T", outer2.Bug0Field)
	}
	if inner.A != 7 {
	t.Fatalf("final value %d; expected %d", inner.A, 7)
	}
	}