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Source file src/encoding/ascii85/ascii85_test.go

Documentation: encoding/ascii85

  // 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 ascii85
  
  import (
  	"bytes"
  	"io"
  	"io/ioutil"
  	"strings"
  	"testing"
  )
  
  type testpair struct {
  	decoded, encoded string
  }
  
  var bigtest = testpair{
  	"Man is distinguished, not only by his reason, but by this singular passion from " +
  		"other animals, which is a lust of the mind, that by a perseverance of delight in " +
  		"the continued and indefatigable generation of knowledge, exceeds the short " +
  		"vehemence of any carnal pleasure.",
  	"9jqo^BlbD-BleB1DJ+*+F(f,q/0JhKF<GL>Cj@.4Gp$d7F!,L7@<6@)/0JDEF<G%<+EV:2F!,\n" +
  		"O<DJ+*.@<*K0@<6L(Df-\\0Ec5e;DffZ(EZee.Bl.9pF\"AGXBPCsi+DGm>@3BB/F*&OCAfu2/AKY\n" +
  		"i(DIb:@FD,*)+C]U=@3BN#EcYf8ATD3s@q?d$AftVqCh[NqF<G:8+EV:.+Cf>-FD5W8ARlolDIa\n" +
  		"l(DId<j@<?3r@:F%a+D58'ATD4$Bl@l3De:,-DJs`8ARoFb/0JMK@qB4^F!,R<AKZ&-DfTqBG%G\n" +
  		">uD.RTpAKYo'+CT/5+Cei#DII?(E,9)oF*2M7/c\n",
  }
  
  var pairs = []testpair{
  	// Encode returns 0 when len(src) is 0
  	{
  		"",
  		"",
  	},
  	// Wikipedia example
  	bigtest,
  	// Special case when shortening !!!!! to z.
  	{
  		"\000\000\000\000",
  		"z",
  	},
  }
  
  func testEqual(t *testing.T, msg string, args ...interface{}) bool {
  	t.Helper()
  	if args[len(args)-2] != args[len(args)-1] {
  		t.Errorf(msg, args...)
  		return false
  	}
  	return true
  }
  
  func strip85(s string) string {
  	t := make([]byte, len(s))
  	w := 0
  	for r := 0; r < len(s); r++ {
  		c := s[r]
  		if c > ' ' {
  			t[w] = c
  			w++
  		}
  	}
  	return string(t[0:w])
  }
  
  func TestEncode(t *testing.T) {
  	for _, p := range pairs {
  		buf := make([]byte, MaxEncodedLen(len(p.decoded)))
  		n := Encode(buf, []byte(p.decoded))
  		buf = buf[0:n]
  		testEqual(t, "Encode(%q) = %q, want %q", p.decoded, strip85(string(buf)), strip85(p.encoded))
  	}
  }
  
  func TestEncoder(t *testing.T) {
  	for _, p := range pairs {
  		bb := &bytes.Buffer{}
  		encoder := NewEncoder(bb)
  		encoder.Write([]byte(p.decoded))
  		encoder.Close()
  		testEqual(t, "Encode(%q) = %q, want %q", p.decoded, strip85(bb.String()), strip85(p.encoded))
  	}
  }
  
  func TestEncoderBuffering(t *testing.T) {
  	input := []byte(bigtest.decoded)
  	for bs := 1; bs <= 12; bs++ {
  		bb := &bytes.Buffer{}
  		encoder := NewEncoder(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, strip85(bb.String()), strip85(bigtest.encoded))
  	}
  }
  
  func TestDecode(t *testing.T) {
  	for _, p := range pairs {
  		dbuf := make([]byte, 4*len(p.encoded))
  		ndst, nsrc, err := Decode(dbuf, []byte(p.encoded), true)
  		testEqual(t, "Decode(%q) = error %v, want %v", p.encoded, err, error(nil))
  		testEqual(t, "Decode(%q) = nsrc %v, want %v", p.encoded, nsrc, len(p.encoded))
  		testEqual(t, "Decode(%q) = ndst %v, want %v", p.encoded, ndst, len(p.decoded))
  		testEqual(t, "Decode(%q) = %q, want %q", p.encoded, string(dbuf[0:ndst]), p.decoded)
  	}
  }
  
  func TestDecoder(t *testing.T) {
  	for _, p := range pairs {
  		decoder := NewDecoder(strings.NewReader(p.encoded))
  		dbuf, err := ioutil.ReadAll(decoder)
  		if err != nil {
  			t.Fatal("Read failed", err)
  		}
  		testEqual(t, "Read from %q = length %v, want %v", p.encoded, len(dbuf), len(p.decoded))
  		testEqual(t, "Decoding of %q = %q, want %q", p.encoded, string(dbuf), p.decoded)
  		if err != nil {
  			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(strings.NewReader(bigtest.encoded))
  		buf := make([]byte, len(bigtest.decoded)+12)
  		var total int
  		var n int
  		var err error
  		for total = 0; total < len(bigtest.decoded) && err == nil; {
  			n, err = decoder.Read(buf[total : total+bs])
  			total += n
  		}
  		if err != nil && err != io.EOF {
  			t.Errorf("Read from %q at pos %d = %d, unexpected error %v", bigtest.encoded, total, n, err)
  		}
  		testEqual(t, "Decoding/%d of %q = %q, want %q", bs, bigtest.encoded, string(buf[0:total]), bigtest.decoded)
  	}
  }
  
  func TestDecodeCorrupt(t *testing.T) {
  	type corrupt struct {
  		e string
  		p int
  	}
  	examples := []corrupt{
  		{"v", 0},
  		{"!z!!!!!!!!!", 1},
  	}
  
  	for _, e := range examples {
  		dbuf := make([]byte, 4*len(e.e))
  		_, _, err := Decode(dbuf, []byte(e.e), true)
  		switch err := err.(type) {
  		case CorruptInputError:
  			testEqual(t, "Corruption in %q at offset %v, want %v", e.e, int(err), e.p)
  		default:
  			t.Error("Decoder failed to detect corruption in", e)
  		}
  	}
  }
  
  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(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(encoded))
  	if err != nil {
  		t.Fatalf("io.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 TestDecoderInternalWhitespace(t *testing.T) {
  	s := strings.Repeat(" ", 2048) + "z"
  	decoded, err := ioutil.ReadAll(NewDecoder(strings.NewReader(s)))
  	if err != nil {
  		t.Errorf("Decode gave error %v", err)
  	}
  	if want := []byte("\000\000\000\000"); !bytes.Equal(want, decoded) {
  		t.Errorf("Decode failed: got %v, want %v", decoded, want)
  	}
  }
  

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