1 files changed, 275 insertions, 0 deletions
diff --git a/src/compress/gzip/gzip_test.go b/src/compress/gzip/gzip_test.go
new file mode 100644
index 0000000..12c8e18
--- /dev/null
+++ b/src/compress/gzip/gzip_test.go
@@ -0,0 +1,275 @@
+// 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 gzip
+
+import (
+	"bufio"
+	"bytes"
+	"io"
+	"reflect"
+	"testing"
+	"time"
+)
+
+// TestEmpty tests that an empty payload still forms a valid GZIP stream.
+func TestEmpty(t *testing.T) {
+	buf := new(bytes.Buffer)
+
+	if err := NewWriter(buf).Close(); err != nil {
+		t.Fatalf("Writer.Close: %v", err)
+	}
+
+	r, err := NewReader(buf)
+	if err != nil {
+		t.Fatalf("NewReader: %v", err)
+	}
+	if want := (Header{OS: 255}); !reflect.DeepEqual(r.Header, want) {
+		t.Errorf("Header mismatch:\ngot  %#v\nwant %#v", r.Header, want)
+	}
+	b, err := io.ReadAll(r)
+	if err != nil {
+		t.Fatalf("ReadAll: %v", err)
+	}
+	if len(b) != 0 {
+		t.Fatalf("got %d bytes, want 0", len(b))
+	}
+	if err := r.Close(); err != nil {
+		t.Fatalf("Reader.Close: %v", err)
+	}
+}
+
+// TestRoundTrip tests that gzipping and then gunzipping is the identity
+// function.
+func TestRoundTrip(t *testing.T) {
+	buf := new(bytes.Buffer)
+
+	w := NewWriter(buf)
+	w.Comment = "comment"
+	w.Extra = []byte("extra")
+	w.ModTime = time.Unix(1e8, 0)
+	w.Name = "name"
+	if _, err := w.Write([]byte("payload")); err != nil {
+		t.Fatalf("Write: %v", err)
+	}
+	if err := w.Close(); err != nil {
+		t.Fatalf("Writer.Close: %v", err)
+	}
+
+	r, err := NewReader(buf)
+	if err != nil {
+		t.Fatalf("NewReader: %v", err)
+	}
+	b, err := io.ReadAll(r)
+	if err != nil {
+		t.Fatalf("ReadAll: %v", err)
+	}
+	if string(b) != "payload" {
+		t.Fatalf("payload is %q, want %q", string(b), "payload")
+	}
+	if r.Comment != "comment" {
+		t.Fatalf("comment is %q, want %q", r.Comment, "comment")
+	}
+	if string(r.Extra) != "extra" {
+		t.Fatalf("extra is %q, want %q", r.Extra, "extra")
+	}
+	if r.ModTime.Unix() != 1e8 {
+		t.Fatalf("mtime is %d, want %d", r.ModTime.Unix(), uint32(1e8))
+	}
+	if r.Name != "name" {
+		t.Fatalf("name is %q, want %q", r.Name, "name")
+	}
+	if err := r.Close(); err != nil {
+		t.Fatalf("Reader.Close: %v", err)
+	}
+}
+
+// TestLatin1 tests the internal functions for converting to and from Latin-1.
+func TestLatin1(t *testing.T) {
+	latin1 := []byte{0xc4, 'u', 0xdf, 'e', 'r', 'u', 'n', 'g', 0}
+	utf8 := "Äußerung"
+	z := Reader{r: bufio.NewReader(bytes.NewReader(latin1))}
+	s, err := z.readString()
+	if err != nil {
+		t.Fatalf("readString: %v", err)
+	}
+	if s != utf8 {
+		t.Fatalf("read latin-1: got %q, want %q", s, utf8)
+	}
+
+	buf := bytes.NewBuffer(make([]byte, 0, len(latin1)))
+	c := Writer{w: buf}
+	if err = c.writeString(utf8); err != nil {
+		t.Fatalf("writeString: %v", err)
+	}
+	s = buf.String()
+	if s != string(latin1) {
+		t.Fatalf("write utf-8: got %q, want %q", s, string(latin1))
+	}
+}
+
+// TestLatin1RoundTrip tests that metadata that is representable in Latin-1
+// survives a round trip.
+func TestLatin1RoundTrip(t *testing.T) {
+	testCases := []struct {
+		name string
+		ok   bool
+	}{
+		{"", true},
+		{"ASCII is OK", true},
+		{"unless it contains a NUL\x00", false},
+		{"no matter where \x00 occurs", false},
+		{"\x00\x00\x00", false},
+		{"Látin-1 also passes (U+00E1)", true},
+		{"but LĀtin Extended-A (U+0100) does not", false},
+		{"neither does 日本語", false},
+		{"invalid UTF-8 also \xffails", false},
+		{"\x00 as does Látin-1 with NUL", false},
+	}
+	for _, tc := range testCases {
+		buf := new(bytes.Buffer)
+
+		w := NewWriter(buf)
+		w.Name = tc.name
+		err := w.Close()
+		if (err == nil) != tc.ok {
+			t.Errorf("Writer.Close: name = %q, err = %v", tc.name, err)
+			continue
+		}
+		if !tc.ok {
+			continue
+		}
+
+		r, err := NewReader(buf)
+		if err != nil {
+			t.Errorf("NewReader: %v", err)
+			continue
+		}
+		_, err = io.ReadAll(r)
+		if err != nil {
+			t.Errorf("ReadAll: %v", err)
+			continue
+		}
+		if r.Name != tc.name {
+			t.Errorf("name is %q, want %q", r.Name, tc.name)
+			continue
+		}
+		if err := r.Close(); err != nil {
+			t.Errorf("Reader.Close: %v", err)
+			continue
+		}
+	}
+}
+
+func TestWriterFlush(t *testing.T) {
+	buf := new(bytes.Buffer)
+
+	w := NewWriter(buf)
+	w.Comment = "comment"
+	w.Extra = []byte("extra")
+	w.ModTime = time.Unix(1e8, 0)
+	w.Name = "name"
+
+	n0 := buf.Len()
+	if n0 != 0 {
+		t.Fatalf("buffer size = %d before writes; want 0", n0)
+	}
+
+	if err := w.Flush(); err != nil {
+		t.Fatal(err)
+	}
+
+	n1 := buf.Len()
+	if n1 == 0 {
+		t.Fatal("no data after first flush")
+	}
+
+	w.Write([]byte("x"))
+
+	n2 := buf.Len()
+	if n1 != n2 {
+		t.Fatalf("after writing a single byte, size changed from %d to %d; want no change", n1, n2)
+	}
+
+	if err := w.Flush(); err != nil {
+		t.Fatal(err)
+	}
+
+	n3 := buf.Len()
+	if n2 == n3 {
+		t.Fatal("Flush didn't flush any data")
+	}
+}
+
+// Multiple gzip files concatenated form a valid gzip file.
+func TestConcat(t *testing.T) {
+	var buf bytes.Buffer
+	w := NewWriter(&buf)
+	w.Write([]byte("hello "))
+	w.Close()
+	w = NewWriter(&buf)
+	w.Write([]byte("world\n"))
+	w.Close()
+
+	r, err := NewReader(&buf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	data, err := io.ReadAll(r)
+	if string(data) != "hello world\n" || err != nil {
+		t.Fatalf("ReadAll = %q, %v, want %q, nil", data, err, "hello world")
+	}
+}
+
+func TestWriterReset(t *testing.T) {
+	buf := new(bytes.Buffer)
+	buf2 := new(bytes.Buffer)
+	z := NewWriter(buf)
+	msg := []byte("hello world")
+	z.Write(msg)
+	z.Close()
+	z.Reset(buf2)
+	z.Write(msg)
+	z.Close()
+	if buf.String() != buf2.String() {
+		t.Errorf("buf2 %q != original buf of %q", buf2.String(), buf.String())
+	}
+}
+
+type limitedWriter struct {
+	N int
+}
+
+func (l *limitedWriter) Write(p []byte) (n int, err error) {
+	if n := l.N; n < len(p) {
+		l.N = 0
+		return n, io.ErrShortWrite
+	}
+	l.N -= len(p)
+	return len(p), nil
+}
+
+// Write should never return more bytes than the input slice.
+func TestLimitedWrite(t *testing.T) {
+	msg := []byte("a")
+
+	for lim := 2; lim < 20; lim++ {
+		z := NewWriter(&limitedWriter{lim})
+		if n, _ := z.Write(msg); n > len(msg) {
+			t.Errorf("Write() = %d, want %d or less", n, len(msg))
+		}
+
+		z.Reset(&limitedWriter{lim})
+		z.Header = Header{
+			Comment: "comment",
+			Extra:   []byte("extra"),
+			ModTime: time.Now(),
+			Name:    "name",
+			OS:      1,
+		}
+		if n, _ := z.Write(msg); n > len(msg) {
+			t.Errorf("Write() = %d, want %d or less", n, len(msg))
+		}
+	}
+}