buf := make([]byte, 1)
	if _, err := b.Read(nil); err != nil {
		t.Fatalf("1st nil Read = %v; want nil", err)
	}
	if _, err := b.Read(buf); err != errFake {
		t.Fatalf("1st Read = %v; want errFake", err)
	}
	if _, err := b.Read(nil); err != nil {
		t.Fatalf("2nd nil Read = %v; want nil", err)
	}
	if _, err := b.Read(buf); err != nil {
		t.Fatalf("3rd Read with buffer = %v; want nil", err)
	}

	// check not at EOF
	b.WriteString("abcdefghijklmnopqrstuvwxyz")

	// after unsuccessful read
	if n, err := b.Read(nil); n != 0 || err != nil {
		t.Fatalf("Read(nil) = %d,%v; want 0,nil", n, err)
	}
	if err := b.UnreadByte(); err == nil {
		t.Fatal("UnreadByte after Read(nil): got no error")
	}

	// after successful read
	if _, err := b.ReadBytes('m'); err != nil {
		t.Fatalf("ReadBytes: %v", err)
	}

	if z.Comment != zt.Comment {
		t.Errorf("comment=%q, want %q", z.Comment, zt.Comment)
	}
	if len(z.File) != len(zt.File) {
		t.Fatalf("file count=%d, want %d", len(z.File), len(zt.File))
	}

	// test read of each file
	for i, ft := range zt.File {
		readTestFile(t, zt, ft, z.File[i], raw)
	}
	if t.Failed() {
		return
	}

	// test simultaneous reads
	n := 0
	done := make(chan bool)

}

var errUnreadByte = errors.New("bytes.Buffer: UnreadByte: previous operation was not a successful read")

// UnreadByte unreads the last byte returned by the most recent successful
// read operation that read at least one byte. If a write has happened since
// the last read, if the last read returned an error, or if the read read zero
// bytes, UnreadByte returns an error.
func (b *Buffer) UnreadByte() error {

		Method: Deflate,
		Mode:   0755 | fs.ModeDevice | fs.ModeCharDevice,
	},
}

func TestWriter(t *testing.T) {
	largeData := make([]byte, 1<<17)
	if _, err := rand.Read(largeData); err != nil {
		t.Fatal("rand.Read failed:", err)
	}
	writeTests[1].Data = largeData
	defer func() {
		writeTests[1].Data = nil
	}()

	// write a zip file
	buf := new(bytes.Buffer)
	w := NewWriter(buf)

	return &pooledFlateReader{fr: fr}
}

type pooledFlateReader struct {
	mu sync.Mutex // guards Close and Read
	fr io.ReadCloser
}

func (r *pooledFlateReader) Read(p []byte) (n int, err error) {
	r.mu.Lock()
	defer r.mu.Unlock()
	if r.fr == nil {
		return 0, errors.New("Read after Close")
	}
	return r.fr.Read(p)
}

func (r *pooledFlateReader) Close() error {
	r.mu.Lock()
	defer r.mu.Unlock()
	var err error

			link(path, link, callback) { callback(enosys()); },
			lstat(path, callback) { callback(enosys()); },
			mkdir(path, perm, callback) { callback(enosys()); },
			open(path, flags, mode, callback) { callback(enosys()); },
			read(fd, buffer, offset, length, position, callback) { callback(enosys()); },
			readdir(path, callback) { callback(enosys()); },
			readlink(path, callback) { callback(enosys()); },
			rename(from, to, callback) { callback(enosys()); },

	}
	return ast1
}

func sourceLine(n ast.Node) int {
	return fset.Position(n.Pos()).Line
}

// ParseGo populates f with information learned from the Go source code
// which was read from the named file. It gathers the C preamble
// attached to the import "C" comment, a list of references to C.xxx,
// a list of exported functions, and the actual AST, to be rewritten and
// printed.

import (
	. "bytes"
	"syscall"
	"testing"
)

// This file tests the situation where byte operations are checking
// data very near to a page boundary. We want to make sure those
// operations do not read across the boundary and cause a page
// fault where they shouldn't.

// These tests run only on linux. The code being tested is
// not OS-specific, so it does not need to be tested on all
// operating systems.

// Read is never called with an empty buffer.
type testNonEmptyReader struct{ io.Reader }

func (r testNonEmptyReader) Read(b []byte) (int, error) {
	if len(b) == 0 {
		return 0, errors.New("unexpected empty Read call")
	}
	return r.Reader.Read(b)
}

func TestFileReader(t *testing.T) {
	type (
		testRead struct { // Read(cnt) == (wantStr, wantErr)
			cnt     int