if err := b.UnreadByte(); err == nil {
		t.Fatal("UnreadByte after ReadByte at EOF: got no error")
	}

	// 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")
	}

				s, ok := spec.(*ast.ImportSpec)
				if !ok || s.Path.Value != `"C"` {
					continue
				}
				sawC = true
				if s.Name != nil {
					error_(s.Path.Pos(), `cannot rename import "C"`)
				}
				cg := s.Doc
				if cg == nil && len(decl.Specs) == 1 {
					cg = decl.Doc
				}
				if cg != nil {
					if strings.ContainsAny(abspath, "\r\n") {
						// This should have been checked when the file path was first resolved,

		{"01234567\x0089abcdef", 342391, true},
		{"0123\x7e\x5f\x264123", 0, false},
	}

	for _, v := range vectors {
		var p parser
		got := p.parseNumeric([]byte(v.in))
		ok := (p.err == nil)
		if ok != v.ok {
			if v.ok {
				t.Errorf("parseNumeric(%q): got parsing failure, want success", v.in)
			} else {
				t.Errorf("parseNumeric(%q): got parsing success, want failure", v.in)
			}
		}

pkg go/types, method (*Named) Underlying() Type
pkg go/types, method (*Nil) Exported() bool
pkg go/types, method (*Nil) Id() string
pkg go/types, method (*Nil) Name() string
pkg go/types, method (*Nil) Parent() *Scope
pkg go/types, method (*Nil) Pkg() *Package
pkg go/types, method (*Nil) Pos() token.Pos
pkg go/types, method (*Nil) String() string
pkg go/types, method (*Nil) Type() Type
pkg go/types, method (*Package) Complete() bool

// 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
}

func OpenReader(name string) (*ReadCloser, error) {
	f, err := os.Open(name)
	if err != nil {
		return nil, err
	}
	fi, err := f.Stat()
	if err != nil {
		f.Close()
		return nil, err
	}
	r := new(ReadCloser)
	if err = r.init(f, fi.Size()); err != nil && err != ErrInsecurePath {
		f.Close()
		return nil, err
	}
	r.f = f
	return r, err
}

	if atEOF && len(data) == 0 {
		return 0, nil, nil
	}
	if i := bytes.IndexByte(data, '\n'); i >= 0 {
		// We have a full newline-terminated line.
		return i + 1, dropCR(data[0:i]), nil
	}
	// If we're at EOF, we have a final, non-terminated line. Return it.
	if atEOF {
		return len(data), dropCR(data), nil
	}
	// Request more data.
	return 0, nil, nil
}

	if err != nil {
		t.Fatal(err)
	}
	if _, err := dw.Write(nil); err != nil {
		t.Errorf("Write(nil) to directory: got %v, want nil", err)
	}
	if _, err := dw.Write([]byte("hello")); err == nil {
		t.Error(`Write("hello") to directory: got nil error, want non-nil`)
	}
}

func TestWriterDirAttributes(t *testing.T) {
	var buf bytes.Buffer
	w := NewWriter(&buf)
	if _, err := w.CreateHeader(&FileHeader{

// String returns the contents of the unread portion of the buffer
// as a string. If the [Buffer] is a nil pointer, it returns "<nil>".
//
// To build strings more efficiently, see the strings.Builder type.
func (b *Buffer) String() string {
	if b == nil {
		// Special case, useful in debugging.
		return "<nil>"
	}
	return string(b.buf[b.off:])
}

// empty reports whether the unread portion of the buffer is empty.

			f, err := os.Open(v.file)
			if err != nil {
				t.Fatalf("Open() error: %v", err)
			}
			defer f.Close()

			tr := NewReader(f)
			for i, tc := range v.cases {
				hdr, err := tr.Next()
				if err != nil || hdr == nil {
					t.Fatalf("entry %d, Next(): got %v, want %v", i, err, nil)
				}
				buf := make([]byte, tc.cnt)
				if _, err := io.ReadFull(tr, buf); err != nil {