src/encoding/base64/base64_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 base64

 import (
 	"bytes"
 	"errors"
 	"io"
 	"io/ioutil"
 	"reflect"
 	"strings"
 	"testing"
 	"time"
 )

 type testpair struct {
 	decoded, encoded string
 }

 var pairs = []testpair{
 	// RFC 3548 examples
 	{"\x14\xfb\x9c\x03\xd9\x7e", "FPucA9l+"},
 	{"\x14\xfb\x9c\x03\xd9", "FPucA9k="},
 	{"\x14\xfb\x9c\x03", "FPucAw=="},

 	// RFC 4648 examples
 	{"", ""},
 	{"f", "Zg=="},
 	{"fo", "Zm8="},
 	{"foo", "Zm9v"},
 	{"foob", "Zm9vYg=="},
 	{"fooba", "Zm9vYmE="},
 	{"foobar", "Zm9vYmFy"},

 	// Wikipedia examples
 	{"sure.", "c3VyZS4="},
 	{"sure", "c3VyZQ=="},
 	{"sur", "c3Vy"},
 	{"su", "c3U="},
 	{"leasure.", "bGVhc3VyZS4="},
 	{"easure.", "ZWFzdXJlLg=="},
 	{"asure.", "YXN1cmUu"},
 	{"sure.", "c3VyZS4="},
 }

 // Do nothing to a reference base64 string (leave in standard format)
 func stdRef(ref string) string {
 	return ref
 }

 // Convert a reference string to URL-encoding
 func urlRef(ref string) string {
 	ref = strings.Replace(ref, "+", "-", -1)
 	ref = strings.Replace(ref, "/", "_", -1)
 	return ref
 }

 // Convert a reference string to raw, unpadded format
 func rawRef(ref string) string {
 	return strings.TrimRight(ref, "=")
 }

 // Both URL and unpadding conversions
 func rawUrlRef(ref string) string {
 	return rawRef(urlRef(ref))
 }

 // A nonstandard encoding with a funny padding character, for testing
 var funnyEncoding = NewEncoding(encodeStd).WithPadding(rune('@'))

 func funnyRef(ref string) string {
 	return strings.Replace(ref, "=", "@", -1)
 }

 type encodingTest struct {
 	enc  *Encoding           // Encoding to test
 	conv func(string) string // Reference string converter
 }

 var encodingTests = []encodingTest{
 	{StdEncoding, stdRef},
 	{URLEncoding, urlRef},
 	{RawStdEncoding, rawRef},
 	{RawURLEncoding, rawUrlRef},
 	{funnyEncoding, funnyRef},
 }

 var bigtest = testpair{
 	"Twas brillig, and the slithy toves",
 	"VHdhcyBicmlsbGlnLCBhbmQgdGhlIHNsaXRoeSB0b3Zlcw==",
 }

 func testEqual(t *testing.T, msg string, args ...interface{}) bool {
 	if args[len(args)-2] != args[len(args)-1] {
 		t.Errorf(msg, args...)
 		return false
 	}
 	return true
 }

 func TestEncode(t *testing.T) {
 	for _, p := range pairs {
 		for _, tt := range encodingTests {
 			got := tt.enc.EncodeToString([]byte(p.decoded))
 			testEqual(t, "Encode(%q) = %q, want %q", p.decoded,
 				got, tt.conv(p.encoded))
 		}
 	}
 }

 func TestEncoder(t *testing.T) {
 	for _, p := range pairs {
 		bb := &bytes.Buffer{}
 		encoder := NewEncoder(StdEncoding, bb)
 		encoder.Write([]byte(p.decoded))
 		encoder.Close()
 		testEqual(t, "Encode(%q) = %q, want %q", p.decoded, bb.String(), p.encoded)
 	}
 }

 func TestEncoderBuffering(t *testing.T) {
 	input := []byte(bigtest.decoded)
 	for bs := 1; bs <= 12; bs++ {
 		bb := &bytes.Buffer{}
 		encoder := NewEncoder(StdEncoding, bb)
 		for pos := 0; pos < len(input); pos += bs {
 			end := pos + bs
 			if end > len(input) {
 				end = len(input)
 			}
 			n, err := encoder.Write(input[pos:end])
 			testEqual(t, "Write(%q) gave error %v, want %v", input[pos:end], err, error(nil))
 			testEqual(t, "Write(%q) gave length %v, want %v", input[pos:end], n, end-pos)
 		}
 		err := encoder.Close()
 		testEqual(t, "Close gave error %v, want %v", err, error(nil))
 		testEqual(t, "Encoding/%d of %q = %q, want %q", bs, bigtest.decoded, bb.String(), bigtest.encoded)
 	}
 }

 func TestDecode(t *testing.T) {
 	for _, p := range pairs {
 		for _, tt := range encodingTests {
 			encoded := tt.conv(p.encoded)
 			dbuf := make([]byte, tt.enc.DecodedLen(len(encoded)))
 			count, end, err := tt.enc.decode(dbuf, []byte(encoded))
 			testEqual(t, "Decode(%q) = error %v, want %v", encoded, err, error(nil))
 			testEqual(t, "Decode(%q) = length %v, want %v", encoded, count, len(p.decoded))
 			if len(encoded) > 0 {
 				testEqual(t, "Decode(%q) = end %v, want %v", encoded, end, len(p.decoded)%3 != 0)
 			}
 			testEqual(t, "Decode(%q) = %q, want %q", encoded, string(dbuf[0:count]), p.decoded)

 			dbuf, err = tt.enc.DecodeString(encoded)
 			testEqual(t, "DecodeString(%q) = error %v, want %v", encoded, err, error(nil))
 			testEqual(t, "DecodeString(%q) = %q, want %q", string(dbuf), p.decoded)
 		}
 	}
 }

 func TestDecoder(t *testing.T) {
 	for _, p := range pairs {
 		decoder := NewDecoder(StdEncoding, strings.NewReader(p.encoded))
 		dbuf := make([]byte, StdEncoding.DecodedLen(len(p.encoded)))
 		count, err := decoder.Read(dbuf)
 		if err != nil && err != io.EOF {
 			t.Fatal("Read failed", err)
 		}
 		testEqual(t, "Read from %q = length %v, want %v", p.encoded, count, len(p.decoded))
 		testEqual(t, "Decoding of %q = %q, want %q", p.encoded, string(dbuf[0:count]), p.decoded)
 		if err != io.EOF {
 			count, err = decoder.Read(dbuf)
 		}
 		testEqual(t, "Read from %q = %v, want %v", p.encoded, err, io.EOF)
 	}
 }

 func TestDecoderBuffering(t *testing.T) {
 	for bs := 1; bs <= 12; bs++ {
 		decoder := NewDecoder(StdEncoding, strings.NewReader(bigtest.encoded))
 		buf := make([]byte, len(bigtest.decoded)+12)
 		var total int
 		for total = 0; total < len(bigtest.decoded); {
 			n, err := decoder.Read(buf[total : total+bs])
 			testEqual(t, "Read from %q at pos %d = %d, %v, want _, %v", bigtest.encoded, total, n, err, error(nil))
 			total += n
 		}
 		testEqual(t, "Decoding/%d of %q = %q, want %q", bs, bigtest.encoded, string(buf[0:total]), bigtest.decoded)
 	}
 }

 func TestDecodeCorrupt(t *testing.T) {
 	testCases := []struct {
 		input  string
 		offset int // -1 means no corruption.
 	}{
 		{"", -1},
 		{"!!!!", 0},
 		{"====", 0},
 		{"x===", 1},
 		{"=AAA", 0},
 		{"A=AA", 1},
 		{"AA=A", 2},
 		{"AA==A", 4},
 		{"AAA=AAAA", 4},
 		{"AAAAA", 4},
 		{"AAAAAA", 4},
 		{"A=", 1},
 		{"A==", 1},
 		{"AA=", 3},
 		{"AA==", -1},
 		{"AAA=", -1},
 		{"AAAA", -1},
 		{"AAAAAA=", 7},
 		{"YWJjZA=====", 8},
 	}
 	for _, tc := range testCases {
 		dbuf := make([]byte, StdEncoding.DecodedLen(len(tc.input)))
 		_, err := StdEncoding.Decode(dbuf, []byte(tc.input))
 		if tc.offset == -1 {
 			if err != nil {
 				t.Error("Decoder wrongly detected corruption in", tc.input)
 			}
 			continue
 		}
 		switch err := err.(type) {
 		case CorruptInputError:
 			testEqual(t, "Corruption in %q at offset %v, want %v", tc.input, int(err), tc.offset)
 		default:
 			t.Error("Decoder failed to detect corruption in", tc)
 		}
 	}
 }

 func TestEncodedLen(t *testing.T) {
 	for _, tt := range []struct {
 		enc  *Encoding
 		n    int
 		want int
 	}{
 		{RawStdEncoding, 0, 0},
 		{RawStdEncoding, 1, 2},
 		{RawStdEncoding, 2, 3},
 		{RawStdEncoding, 3, 4},
 		{RawStdEncoding, 7, 10},
 		{StdEncoding, 0, 0},
 		{StdEncoding, 1, 4},
 		{StdEncoding, 2, 4},
 		{StdEncoding, 3, 4},
 		{StdEncoding, 4, 8},
 		{StdEncoding, 7, 12},
 	} {
 		if got := tt.enc.EncodedLen(tt.n); got != tt.want {
 			t.Errorf("EncodedLen(%d): got %d, want %d", tt.n, got, tt.want)
 		}
 	}
 }

 func TestDecodedLen(t *testing.T) {
 	for _, tt := range []struct {
 		enc  *Encoding
 		n    int
 		want int
 	}{
 		{RawStdEncoding, 0, 0},
 		{RawStdEncoding, 2, 1},
 		{RawStdEncoding, 3, 2},
 		{RawStdEncoding, 4, 3},
 		{RawStdEncoding, 10, 7},
 		{StdEncoding, 0, 0},
 		{StdEncoding, 4, 3},
 		{StdEncoding, 8, 6},
 	} {
 		if got := tt.enc.DecodedLen(tt.n); got != tt.want {
 			t.Errorf("DecodedLen(%d): got %d, want %d", tt.n, got, tt.want)
 		}
 	}
 }

 func TestBig(t *testing.T) {
 	n := 3*1000 + 1
 	raw := make([]byte, n)
 	const alpha = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
 	for i := 0; i < n; i++ {
 		raw[i] = alpha[i%len(alpha)]
 	}
 	encoded := new(bytes.Buffer)
 	w := NewEncoder(StdEncoding, encoded)
 	nn, err := w.Write(raw)
 	if nn != n || err != nil {
 		t.Fatalf("Encoder.Write(raw) = %d, %v want %d, nil", nn, err, n)
 	}
 	err = w.Close()
 	if err != nil {
 		t.Fatalf("Encoder.Close() = %v want nil", err)
 	}
 	decoded, err := ioutil.ReadAll(NewDecoder(StdEncoding, encoded))
 	if err != nil {
 		t.Fatalf("ioutil.ReadAll(NewDecoder(...)): %v", err)
 	}

 	if !bytes.Equal(raw, decoded) {
 		var i int
 		for i = 0; i < len(decoded) && i < len(raw); i++ {
 			if decoded[i] != raw[i] {
 				break
 			}
 		}
 		t.Errorf("Decode(Encode(%d-byte string)) failed at offset %d", n, i)
 	}
 }

 func TestNewLineCharacters(t *testing.T) {
 	// Each of these should decode to the string "sure", without errors.
 	const expected = "sure"
 	examples := []string{
 		"c3VyZQ==",
 		"c3VyZQ==\r",
 		"c3VyZQ==\n",
 		"c3VyZQ==\r\n",
 		"c3VyZ\r\nQ==",
 		"c3V\ryZ\nQ==",
 		"c3V\nyZ\rQ==",
 		"c3VyZ\nQ==",
 		"c3VyZQ\n==",
 		"c3VyZQ=\n=",
 		"c3VyZQ=\r\n\r\n=",
 	}
 	for _, e := range examples {
 		buf, err := StdEncoding.DecodeString(e)
 		if err != nil {
 			t.Errorf("Decode(%q) failed: %v", e, err)
 			continue
 		}
 		if s := string(buf); s != expected {
 			t.Errorf("Decode(%q) = %q, want %q", e, s, expected)
 		}
 	}
 }

 type nextRead struct {
 	n   int   // bytes to return
 	err error // error to return
 }

 // faultInjectReader returns data from source, rate-limited
 // and with the errors as written to nextc.
 type faultInjectReader struct {
 	source string
 	nextc  <-chan nextRead
 }

 func (r *faultInjectReader) Read(p []byte) (int, error) {
 	nr := <-r.nextc
 	if len(p) > nr.n {
 		p = p[:nr.n]
 	}
 	n := copy(p, r.source)
 	r.source = r.source[n:]
 	return n, nr.err
 }

 // tests that we don't ignore errors from our underlying reader
 func TestDecoderIssue3577(t *testing.T) {
 	next := make(chan nextRead, 10)
 	wantErr := errors.New("my error")
 	next <- nextRead{5, nil}
 	next <- nextRead{10, wantErr}
 	next <- nextRead{0, wantErr}
 	d := NewDecoder(StdEncoding, &faultInjectReader{
 		source: "VHdhcyBicmlsbGlnLCBhbmQgdGhlIHNsaXRoeSB0b3Zlcw==", // twas brillig...
 		nextc:  next,
 	})
 	errc := make(chan error)
 	go func() {
 		_, err := ioutil.ReadAll(d)
 		errc <- err
 	}()
 	select {
 	case err := <-errc:
 		if err != wantErr {
 			t.Errorf("got error %v; want %v", err, wantErr)
 		}
 	case <-time.After(5 * time.Second):
 		t.Errorf("timeout; Decoder blocked without returning an error")
 	}
 }

 func TestDecoderIssue4779(t *testing.T) {
 	encoded := `CP/EAT8AAAEF
 AQEBAQEBAAAAAAAAAAMAAQIEBQYHCAkKCwEAAQUBAQEBAQEAAAAAAAAAAQACAwQFBgcICQoLEAAB
 BAEDAgQCBQcGCAUDDDMBAAIRAwQhEjEFQVFhEyJxgTIGFJGhsUIjJBVSwWIzNHKC0UMHJZJT8OHx
 Y3M1FqKygyZEk1RkRcKjdDYX0lXiZfKzhMPTdePzRieUpIW0lcTU5PSltcXV5fVWZnaGlqa2xtbm
 9jdHV2d3h5ent8fX5/cRAAICAQIEBAMEBQYHBwYFNQEAAhEDITESBEFRYXEiEwUygZEUobFCI8FS
 0fAzJGLhcoKSQ1MVY3M08SUGFqKygwcmNcLSRJNUoxdkRVU2dGXi8rOEw9N14/NGlKSFtJXE1OT0
 pbXF1eX1VmZ2hpamtsbW5vYnN0dXZ3eHl6e3x//aAAwDAQACEQMRAD8A9VSSSSUpJJJJSkkkJ+Tj
 1kiy1jCJJDnAcCTykpKkuQ6p/jN6FgmxlNduXawwAzaGH+V6jn/R/wCt71zdn+N/qL3kVYFNYB4N
 ji6PDVjWpKp9TSXnvTf8bFNjg3qOEa2n6VlLpj/rT/pf567DpX1i6L1hs9Py67X8mqdtg/rUWbbf
 +gkp0kkkklKSSSSUpJJJJT//0PVUkkklKVLq3WMDpGI7KzrNjADtYNXvI/Mqr/Pd/q9W3vaxjnvM
 NaCXE9gNSvGPrf8AWS3qmba5jjsJhoB0DAf0NDf6sevf+/lf8Hj0JJATfWT6/dV6oXU1uOLQeKKn
 EQP+Hubtfe/+R7Mf/g7f5xcocp++Z11JMCJPgFBxOg7/AOuqDx8I/ikpkXkmSdU8mJIJA/O8EMAy
 j+mSARB/17pKVXYWHXjsj7yIex0PadzXMO1zT5KHoNA3HT8ietoGhgjsfA+CSnvvqh/jJtqsrwOv
 2b6NGNzXfTYexzJ+nU7/ALkf4P8Awv6P9KvTQQ4AgyDqCF85Pho3CTB7eHwXoH+LT65uZbX9X+o2
 bqbPb06551Y4
 `
 	encodedShort := strings.Replace(encoded, "\n", "", -1)

 	dec := NewDecoder(StdEncoding, strings.NewReader(encoded))
 	res1, err := ioutil.ReadAll(dec)
 	if err != nil {
 		t.Errorf("ReadAll failed: %v", err)
 	}

 	dec = NewDecoder(StdEncoding, strings.NewReader(encodedShort))
 	var res2 []byte
 	res2, err = ioutil.ReadAll(dec)
 	if err != nil {
 		t.Errorf("ReadAll failed: %v", err)
 	}

 	if !bytes.Equal(res1, res2) {
 		t.Error("Decoded results not equal")
 	}
 }

 func TestDecoderIssue7733(t *testing.T) {
 	s, err := StdEncoding.DecodeString("YWJjZA=====")
 	want := CorruptInputError(8)
 	if !reflect.DeepEqual(want, err) {
 		t.Errorf("Error = %v; want CorruptInputError(8)", err)
 	}
 	if string(s) != "abcd" {
 		t.Errorf("DecodeString = %q; want abcd", s)
 	}
 }

 func BenchmarkEncodeToString(b *testing.B) {
 	data := make([]byte, 8192)
 	b.SetBytes(int64(len(data)))
 	for i := 0; i < b.N; i++ {
 		StdEncoding.EncodeToString(data)
 	}
 }

 func BenchmarkDecodeString(b *testing.B) {
 	data := StdEncoding.EncodeToString(make([]byte, 8192))
 	b.SetBytes(int64(len(data)))
 	for i := 0; i < b.N; i++ {
 		StdEncoding.DecodeString(data)
 	}
 }

 func TestDecoderRaw(t *testing.T) {
 	source := "AAAAAA"
 	want := []byte{0, 0, 0, 0}

 	// Direct.
 	dec1, err := RawURLEncoding.DecodeString(source)
 	if err != nil || !bytes.Equal(dec1, want) {
 		t.Errorf("RawURLEncoding.DecodeString(%q) = %x, %v, want %x, nil", source, dec1, err, want)
 	}

 	// Through reader. Used to fail.
 	r := NewDecoder(RawURLEncoding, bytes.NewReader([]byte(source)))
 	dec2, err := ioutil.ReadAll(io.LimitReader(r, 100))
 	if err != nil || !bytes.Equal(dec2, want) {
 		t.Errorf("reading NewDecoder(RawURLEncoding, %q) = %x, %v, want %x, nil", source, dec2, err, want)
 	}

 	// Should work with padding.
 	r = NewDecoder(URLEncoding, bytes.NewReader([]byte(source+"==")))
 	dec3, err := ioutil.ReadAll(r)
 	if err != nil || !bytes.Equal(dec3, want) {
 		t.Errorf("reading NewDecoder(URLEncoding, %q) = %x, %v, want %x, nil", source+"==", dec3, err, want)
 	}
 }
	// 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 base64

	import (
	"bytes"
	"errors"
	"io"
	"io/ioutil"
	"reflect"
	"strings"
	"testing"
	"time"
	)

	type testpair struct {
	decoded, encoded string
	}

	var pairs = []testpair{
	// RFC 3548 examples
	{"\x14\xfb\x9c\x03\xd9\x7e", "FPucA9l+"},
	{"\x14\xfb\x9c\x03\xd9", "FPucA9k="},
	{"\x14\xfb\x9c\x03", "FPucAw=="},

	// RFC 4648 examples
	{"", ""},
	{"f", "Zg=="},
	{"fo", "Zm8="},
	{"foo", "Zm9v"},
	{"foob", "Zm9vYg=="},
	{"fooba", "Zm9vYmE="},
	{"foobar", "Zm9vYmFy"},

	// Wikipedia examples
	{"sure.", "c3VyZS4="},
	{"sure", "c3VyZQ=="},
	{"sur", "c3Vy"},
	{"su", "c3U="},
	{"leasure.", "bGVhc3VyZS4="},
	{"easure.", "ZWFzdXJlLg=="},
	{"asure.", "YXN1cmUu"},
	{"sure.", "c3VyZS4="},
	}

	// Do nothing to a reference base64 string (leave in standard format)
	func stdRef(ref string) string {
	return ref
	}

	// Convert a reference string to URL-encoding
	func urlRef(ref string) string {
	ref = strings.Replace(ref, "+", "-", -1)
	ref = strings.Replace(ref, "/", "_", -1)
	return ref
	}

	// Convert a reference string to raw, unpadded format
	func rawRef(ref string) string {
	return strings.TrimRight(ref, "=")
	}

	// Both URL and unpadding conversions
	func rawUrlRef(ref string) string {
	return rawRef(urlRef(ref))
	}

	// A nonstandard encoding with a funny padding character, for testing
	var funnyEncoding = NewEncoding(encodeStd).WithPadding(rune('@'))

	func funnyRef(ref string) string {
	return strings.Replace(ref, "=", "@", -1)
	}

	type encodingTest struct {
	enc *Encoding // Encoding to test
	conv func(string) string // Reference string converter
	}

	var encodingTests = []encodingTest{
	{StdEncoding, stdRef},
	{URLEncoding, urlRef},
	{RawStdEncoding, rawRef},
	{RawURLEncoding, rawUrlRef},
	{funnyEncoding, funnyRef},
	}

	var bigtest = testpair{
	"Twas brillig, and the slithy toves",
	"VHdhcyBicmlsbGlnLCBhbmQgdGhlIHNsaXRoeSB0b3Zlcw==",
	}

	func testEqual(t *testing.T, msg string, args ...interface{}) bool {
	if args[len(args)-2] != args[len(args)-1] {
	t.Errorf(msg, args...)
	return false
	}
	return true
	}

	func TestEncode(t *testing.T) {
	for _, p := range pairs {
	for _, tt := range encodingTests {
	got := tt.enc.EncodeToString([]byte(p.decoded))
	testEqual(t, "Encode(%q) = %q, want %q", p.decoded,
	got, tt.conv(p.encoded))
	}
	}
	}

	func TestEncoder(t *testing.T) {
	for _, p := range pairs {
	bb := &bytes.Buffer{}
	encoder := NewEncoder(StdEncoding, bb)
	encoder.Write([]byte(p.decoded))
	encoder.Close()
	testEqual(t, "Encode(%q) = %q, want %q", p.decoded, bb.String(), p.encoded)
	}
	}

	func TestEncoderBuffering(t *testing.T) {
	input := []byte(bigtest.decoded)
	for bs := 1; bs <= 12; bs++ {
	bb := &bytes.Buffer{}
	encoder := NewEncoder(StdEncoding, bb)
	for pos := 0; pos < len(input); pos += bs {
	end := pos + bs
	if end > len(input) {
	end = len(input)
	}
	n, err := encoder.Write(input[pos:end])
	testEqual(t, "Write(%q) gave error %v, want %v", input[pos:end], err, error(nil))
	testEqual(t, "Write(%q) gave length %v, want %v", input[pos:end], n, end-pos)
	}
	err := encoder.Close()
	testEqual(t, "Close gave error %v, want %v", err, error(nil))
	testEqual(t, "Encoding/%d of %q = %q, want %q", bs, bigtest.decoded, bb.String(), bigtest.encoded)
	}
	}

	func TestDecode(t *testing.T) {
	for _, p := range pairs {
	for _, tt := range encodingTests {
	encoded := tt.conv(p.encoded)
	dbuf := make([]byte, tt.enc.DecodedLen(len(encoded)))
	count, end, err := tt.enc.decode(dbuf, []byte(encoded))
	testEqual(t, "Decode(%q) = error %v, want %v", encoded, err, error(nil))
	testEqual(t, "Decode(%q) = length %v, want %v", encoded, count, len(p.decoded))
	if len(encoded) > 0 {
	testEqual(t, "Decode(%q) = end %v, want %v", encoded, end, len(p.decoded)%3 != 0)
	}
	testEqual(t, "Decode(%q) = %q, want %q", encoded, string(dbuf[0:count]), p.decoded)

	dbuf, err = tt.enc.DecodeString(encoded)
	testEqual(t, "DecodeString(%q) = error %v, want %v", encoded, err, error(nil))
	testEqual(t, "DecodeString(%q) = %q, want %q", string(dbuf), p.decoded)
	}
	}
	}

	func TestDecoder(t *testing.T) {
	for _, p := range pairs {
	decoder := NewDecoder(StdEncoding, strings.NewReader(p.encoded))
	dbuf := make([]byte, StdEncoding.DecodedLen(len(p.encoded)))
	count, err := decoder.Read(dbuf)
	if err != nil && err != io.EOF {
	t.Fatal("Read failed", err)
	}
	testEqual(t, "Read from %q = length %v, want %v", p.encoded, count, len(p.decoded))
	testEqual(t, "Decoding of %q = %q, want %q", p.encoded, string(dbuf[0:count]), p.decoded)
	if err != io.EOF {
	count, err = decoder.Read(dbuf)
	}
	testEqual(t, "Read from %q = %v, want %v", p.encoded, err, io.EOF)
	}
	}

	func TestDecoderBuffering(t *testing.T) {
	for bs := 1; bs <= 12; bs++ {
	decoder := NewDecoder(StdEncoding, strings.NewReader(bigtest.encoded))
	buf := make([]byte, len(bigtest.decoded)+12)
	var total int
	for total = 0; total < len(bigtest.decoded); {
	n, err := decoder.Read(buf[total : total+bs])
	testEqual(t, "Read from %q at pos %d = %d, %v, want _, %v", bigtest.encoded, total, n, err, error(nil))
	total += n
	}
	testEqual(t, "Decoding/%d of %q = %q, want %q", bs, bigtest.encoded, string(buf[0:total]), bigtest.decoded)
	}
	}

	func TestDecodeCorrupt(t *testing.T) {
	testCases := []struct {
	input string
	offset int // -1 means no corruption.
	}{
	{"", -1},
	{"!!!!", 0},
	{"====", 0},
	{"x===", 1},
	{"=AAA", 0},
	{"A=AA", 1},
	{"AA=A", 2},
	{"AA==A", 4},
	{"AAA=AAAA", 4},
	{"AAAAA", 4},
	{"AAAAAA", 4},
	{"A=", 1},
	{"A==", 1},
	{"AA=", 3},
	{"AA==", -1},
	{"AAA=", -1},
	{"AAAA", -1},
	{"AAAAAA=", 7},
	{"YWJjZA=====", 8},
	}
	for _, tc := range testCases {
	dbuf := make([]byte, StdEncoding.DecodedLen(len(tc.input)))
	_, err := StdEncoding.Decode(dbuf, []byte(tc.input))
	if tc.offset == -1 {
	if err != nil {
	t.Error("Decoder wrongly detected corruption in", tc.input)
	}
	continue
	}
	switch err := err.(type) {
	case CorruptInputError:
	testEqual(t, "Corruption in %q at offset %v, want %v", tc.input, int(err), tc.offset)
	default:
	t.Error("Decoder failed to detect corruption in", tc)
	}
	}
	}

	func TestEncodedLen(t *testing.T) {
	for _, tt := range []struct {
	enc *Encoding
	n int
	want int
	}{
	{RawStdEncoding, 0, 0},
	{RawStdEncoding, 1, 2},
	{RawStdEncoding, 2, 3},
	{RawStdEncoding, 3, 4},
	{RawStdEncoding, 7, 10},
	{StdEncoding, 0, 0},
	{StdEncoding, 1, 4},
	{StdEncoding, 2, 4},
	{StdEncoding, 3, 4},
	{StdEncoding, 4, 8},
	{StdEncoding, 7, 12},
	} {
	if got := tt.enc.EncodedLen(tt.n); got != tt.want {
	t.Errorf("EncodedLen(%d): got %d, want %d", tt.n, got, tt.want)
	}
	}
	}

	func TestDecodedLen(t *testing.T) {
	for _, tt := range []struct {
	enc *Encoding
	n int
	want int
	}{
	{RawStdEncoding, 0, 0},
	{RawStdEncoding, 2, 1},
	{RawStdEncoding, 3, 2},
	{RawStdEncoding, 4, 3},
	{RawStdEncoding, 10, 7},
	{StdEncoding, 0, 0},
	{StdEncoding, 4, 3},
	{StdEncoding, 8, 6},
	} {
	if got := tt.enc.DecodedLen(tt.n); got != tt.want {
	t.Errorf("DecodedLen(%d): got %d, want %d", tt.n, got, tt.want)
	}
	}
	}

	func TestBig(t *testing.T) {
	n := 3*1000 + 1
	raw := make([]byte, n)
	const alpha = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
	for i := 0; i < n; i++ {
	raw[i] = alpha[i%len(alpha)]
	}
	encoded := new(bytes.Buffer)
	w := NewEncoder(StdEncoding, encoded)
	nn, err := w.Write(raw)
	if nn != n \|\| err != nil {
	t.Fatalf("Encoder.Write(raw) = %d, %v want %d, nil", nn, err, n)
	}
	err = w.Close()
	if err != nil {
	t.Fatalf("Encoder.Close() = %v want nil", err)
	}
	decoded, err := ioutil.ReadAll(NewDecoder(StdEncoding, encoded))
	if err != nil {
	t.Fatalf("ioutil.ReadAll(NewDecoder(...)): %v", err)
	}

	if !bytes.Equal(raw, decoded) {
	var i int
	for i = 0; i < len(decoded) && i < len(raw); i++ {
	if decoded[i] != raw[i] {
	break
	}
	}
	t.Errorf("Decode(Encode(%d-byte string)) failed at offset %d", n, i)
	}
	}

	func TestNewLineCharacters(t *testing.T) {
	// Each of these should decode to the string "sure", without errors.
	const expected = "sure"
	examples := []string{
	"c3VyZQ==",
	"c3VyZQ==\r",
	"c3VyZQ==\n",
	"c3VyZQ==\r\n",
	"c3VyZ\r\nQ==",
	"c3V\ryZ\nQ==",
	"c3V\nyZ\rQ==",
	"c3VyZ\nQ==",
	"c3VyZQ\n==",
	"c3VyZQ=\n=",
	"c3VyZQ=\r\n\r\n=",
	}
	for _, e := range examples {
	buf, err := StdEncoding.DecodeString(e)
	if err != nil {
	t.Errorf("Decode(%q) failed: %v", e, err)
	continue
	}
	if s := string(buf); s != expected {
	t.Errorf("Decode(%q) = %q, want %q", e, s, expected)
	}
	}
	}

	type nextRead struct {
	n int // bytes to return
	err error // error to return
	}

	// faultInjectReader returns data from source, rate-limited
	// and with the errors as written to nextc.
	type faultInjectReader struct {
	source string
	nextc <-chan nextRead
	}

	func (r *faultInjectReader) Read(p []byte) (int, error) {
	nr := <-r.nextc
	if len(p) > nr.n {
	p = p[:nr.n]
	}
	n := copy(p, r.source)
	r.source = r.source[n:]
	return n, nr.err
	}

	// tests that we don't ignore errors from our underlying reader
	func TestDecoderIssue3577(t *testing.T) {
	next := make(chan nextRead, 10)
	wantErr := errors.New("my error")
	next <- nextRead{5, nil}
	next <- nextRead{10, wantErr}
	next <- nextRead{0, wantErr}
	d := NewDecoder(StdEncoding, &faultInjectReader{
	source: "VHdhcyBicmlsbGlnLCBhbmQgdGhlIHNsaXRoeSB0b3Zlcw==", // twas brillig...
	nextc: next,
	})
	errc := make(chan error)
	go func() {
	_, err := ioutil.ReadAll(d)
	errc <- err
	}()
	select {
	case err := <-errc:
	if err != wantErr {
	t.Errorf("got error %v; want %v", err, wantErr)
	}
	case <-time.After(5 * time.Second):
	t.Errorf("timeout; Decoder blocked without returning an error")
	}
	}

	func TestDecoderIssue4779(t *testing.T) {
	encoded := `CP/EAT8AAAEF
	AQEBAQEBAAAAAAAAAAMAAQIEBQYHCAkKCwEAAQUBAQEBAQEAAAAAAAAAAQACAwQFBgcICQoLEAAB
	BAEDAgQCBQcGCAUDDDMBAAIRAwQhEjEFQVFhEyJxgTIGFJGhsUIjJBVSwWIzNHKC0UMHJZJT8OHx
	Y3M1FqKygyZEk1RkRcKjdDYX0lXiZfKzhMPTdePzRieUpIW0lcTU5PSltcXV5fVWZnaGlqa2xtbm
	9jdHV2d3h5ent8fX5/cRAAICAQIEBAMEBQYHBwYFNQEAAhEDITESBEFRYXEiEwUygZEUobFCI8FS
	0fAzJGLhcoKSQ1MVY3M08SUGFqKygwcmNcLSRJNUoxdkRVU2dGXi8rOEw9N14/NGlKSFtJXE1OT0
	pbXF1eX1VmZ2hpamtsbW5vYnN0dXZ3eHl6e3x//aAAwDAQACEQMRAD8A9VSSSSUpJJJJSkkkJ+Tj
	1kiy1jCJJDnAcCTykpKkuQ6p/jN6FgmxlNduXawwAzaGH+V6jn/R/wCt71zdn+N/qL3kVYFNYB4N
	ji6PDVjWpKp9TSXnvTf8bFNjg3qOEa2n6VlLpj/rT/pf567DpX1i6L1hs9Py67X8mqdtg/rUWbbf
	+gkp0kkkklKSSSSUpJJJJT//0PVUkkklKVLq3WMDpGI7KzrNjADtYNXvI/Mqr/Pd/q9W3vaxjnvM
	NaCXE9gNSvGPrf8AWS3qmba5jjsJhoB0DAf0NDf6sevf+/lf8Hj0JJATfWT6/dV6oXU1uOLQeKKn
	EQP+Hubtfe/+R7Mf/g7f5xcocp++Z11JMCJPgFBxOg7/AOuqDx8I/ikpkXkmSdU8mJIJA/O8EMAy
	j+mSARB/17pKVXYWHXjsj7yIex0PadzXMO1zT5KHoNA3HT8ietoGhgjsfA+CSnvvqh/jJtqsrwOv
	2b6NGNzXfTYexzJ+nU7/ALkf4P8Awv6P9KvTQQ4AgyDqCF85Pho3CTB7eHwXoH+LT65uZbX9X+o2
	bqbPb06551Y4
	`
	encodedShort := strings.Replace(encoded, "\n", "", -1)

	dec := NewDecoder(StdEncoding, strings.NewReader(encoded))
	res1, err := ioutil.ReadAll(dec)
	if err != nil {
	t.Errorf("ReadAll failed: %v", err)
	}

	dec = NewDecoder(StdEncoding, strings.NewReader(encodedShort))
	var res2 []byte
	res2, err = ioutil.ReadAll(dec)
	if err != nil {
	t.Errorf("ReadAll failed: %v", err)
	}

	if !bytes.Equal(res1, res2) {
	t.Error("Decoded results not equal")
	}
	}

	func TestDecoderIssue7733(t *testing.T) {
	s, err := StdEncoding.DecodeString("YWJjZA=====")
	want := CorruptInputError(8)
	if !reflect.DeepEqual(want, err) {
	t.Errorf("Error = %v; want CorruptInputError(8)", err)
	}
	if string(s) != "abcd" {
	t.Errorf("DecodeString = %q; want abcd", s)
	}
	}

	func BenchmarkEncodeToString(b *testing.B) {
	data := make([]byte, 8192)
	b.SetBytes(int64(len(data)))
	for i := 0; i < b.N; i++ {
	StdEncoding.EncodeToString(data)
	}
	}

	func BenchmarkDecodeString(b *testing.B) {
	data := StdEncoding.EncodeToString(make([]byte, 8192))
	b.SetBytes(int64(len(data)))
	for i := 0; i < b.N; i++ {
	StdEncoding.DecodeString(data)
	}
	}

	func TestDecoderRaw(t *testing.T) {
	source := "AAAAAA"
	want := []byte{0, 0, 0, 0}

	// Direct.
	dec1, err := RawURLEncoding.DecodeString(source)
	if err != nil \|\| !bytes.Equal(dec1, want) {
	t.Errorf("RawURLEncoding.DecodeString(%q) = %x, %v, want %x, nil", source, dec1, err, want)
	}

	// Through reader. Used to fail.
	r := NewDecoder(RawURLEncoding, bytes.NewReader([]byte(source)))
	dec2, err := ioutil.ReadAll(io.LimitReader(r, 100))
	if err != nil \|\| !bytes.Equal(dec2, want) {
	t.Errorf("reading NewDecoder(RawURLEncoding, %q) = %x, %v, want %x, nil", source, dec2, err, want)
	}

	// Should work with padding.
	r = NewDecoder(URLEncoding, bytes.NewReader([]byte(source+"==")))
	dec3, err := ioutil.ReadAll(r)
	if err != nil \|\| !bytes.Equal(dec3, want) {
	t.Errorf("reading NewDecoder(URLEncoding, %q) = %x, %v, want %x, nil", source+"==", dec3, err, want)
	}
	}