// Check that UnreadRune works
	buf.Reset()

	// check at EOF
	if err := buf.UnreadRune(); err == nil {
		t.Fatal("UnreadRune at EOF: got no error")
	}
	if _, _, err := buf.ReadRune(); err == nil {
		t.Fatal("ReadRune at EOF: got no error")
	}
	if err := buf.UnreadRune(); err == nil {
		t.Fatal("UnreadRune after ReadRune at EOF: got no error")
	}

	// check not at EOF
	buf.Write(b)

			Method:  Deflate,
		}
		w, err := w.CreateHeader(h)
		if err != nil {
			t.Fatal(err)
		}
		w.Write([]byte{})
	}

	if err := w.Close(); err != nil {
		t.Fatal(err)
	}

	// read it back
	r, err := NewReader(bytes.NewReader(buf.Bytes()), int64(buf.Len()))
	if err != nil {
		t.Fatal(err)
	}
	for i, test := range utf8Tests {
		flags := r.File[i].Flags
		if flags != test.flags {

		if err != nil {
			t.Fatal("write chunk:", err)
		}
	}
	end := []byte("END\n")
	_, err = f.Write(end)
	if err != nil {
		t.Fatal("write end:", err)
	}
	if err := w.Close(); err != nil {
		t.Fatal(err)
	}

	// read back zip file and check that we get to the end of it
	r, err := NewReader(buf, buf.Size())
	if err != nil {
		t.Fatal("reader:", err)
	}
	f0 := r.File[0]

	if err := writer.WriteHeader(hdr); err != nil {
		t.Fatal(err)
	}
	if _, err = writer.Write([]byte(contents)); err != nil {
		t.Fatal(err)
	}
	if err := writer.Close(); err != nil {
		t.Fatal(err)
	}
	// Simple test to make sure PAX extensions are in effect
	if !bytes.Contains(buf.Bytes(), []byte("PaxHeaders.0")) {
		t.Fatal("Expected at least one PAX header to be written.")
	}

	defer func() {
		err := recover()
		if err == nil {
			t.Fatal("should have panicked")
		}
		if msg, ok := err.(string); !ok || !strings.Contains(msg, "empty tokens") {
			panic(err)
		}
	}()
	for count := 0; s.Scan(); count++ {
		if count > 1000 {
			t.Fatal("looping")
		}
	}
	if s.Err() != nil {
		t.Fatal("after scan:", s.Err())
	}
}

func TestBlankLines(t *testing.T) {

// Returns error gathered from recover; nil if no parse errors occurred.
//
// For unexpected panics, calls t.Fatal.
func tryParse(t *testing.T, parse func()) (err error) {
	panicOnError = true
	defer func() {
		panicOnError = false

		e := recover()
		var ok bool
		if err, ok = e.(error); e != nil && !ok {
			t.Fatal(e)
		}
	}()

	parse()

	return nil
}

	link := filepath.Join(tmpdir, "link")
	target := tmpdir
	if err := os.Symlink(target, link); err != nil {
		t.Fatal(err)
	}
	fi, err := os.Lstat(link)
	if err != nil {
		t.Fatal(err)
	}

	h, err := FileInfoHeader(fi, target)
	if err != nil {
		t.Fatal(err)
	}
	if g, e := h.Name, fi.Name(); g != e {
		t.Errorf("Name = %q; want %q", g, e)
	}
	if g, e := h.Linkname, target; g != e {

pkg testing, method (*F) Errorf(string, ...interface{})
pkg testing, method (*F) Fail()
pkg testing, method (*F) FailNow()
pkg testing, method (*F) Failed() bool
pkg testing, method (*F) Fatal(...interface{})
pkg testing, method (*F) Fatalf(string, ...interface{})
pkg testing, method (*F) Fuzz(interface{})
pkg testing, method (*F) Helper()
pkg testing, method (*F) Log(...interface{})

		tw.err = tw.writePAXHeader(&tw.hdr, paxHdrs)
		return tw.err
	case allowedFormats.has(FormatGNU):
		tw.err = tw.writeGNUHeader(&tw.hdr)
		return tw.err
	default:
		return err // Non-fatal error
	}
}

func (tw *Writer) writeUSTARHeader(hdr *Header) error {
	// Check if we can use USTAR prefix/suffix splitting.
	var namePrefix string
	if prefix, suffix, ok := splitUSTARPath(hdr.Name); ok {

	if err != nil {
		t.Fatal(err)
	}

	var nextFiles []string
	if v := runtime.Version(); strings.Contains(v, "devel") || strings.Contains(v, "beta") {
		next, err := filepath.Glob(filepath.Join(testenv.GOROOT(t), "api/next/*.txt"))
		if err != nil {
			t.Fatal(err)
		}
		nextFiles = next
	}

	for _, c := range contexts {