}
	_, err = NewReader(bytes.NewReader(b), size)
	if err != ErrFormat {
		t.Errorf("sigs: error=%v, want %v", err, ErrFormat)
	}

	// negative size
	_, err = NewReader(bytes.NewReader([]byte("foobar")), -1)
	if err == nil {
		t.Errorf("archive/zip.NewReader: expected error when negative size is passed")
	}
}

func messWith(fileName string, corrupter func(b []byte)) (r io.ReaderAt, size int64) {

			t.Fatalf("ReadRune(0x%x) got 0x%x,%d not 0x%x,%d (err=%s)", r1, nr, nbytes, r1, size, err)
		}
	}
}

func TestWriteInvalidRune(t *testing.T) {
	// Invalid runes, including negative ones, should be written as the
	// replacement character.
	for _, r := range []rune{-1, utf8.MaxRune + 1} {
		var buf strings.Builder
		w := NewWriter(&buf)
		w.WriteRune(r)
		w.Flush()

	// Test other movtab entries.
	PUSHQ GS // 0fa8
	PUSHQ FS // 0fa0
	POPQ FS  // 0fa1
	POPQ GS  // 0fa9
	// All instructions below semantically have unsigned operands,
	// but previous assembler permitted negative arguments.
	// This behavior is preserved for compatibility reasons.
	VPSHUFD $-79, X7, X7         // c5f970ffb1
	RORXL $-1, (AX), DX          // c4e37bf010ff
	RORXQ $-1, (AX), DX          // c4e3fbf010ff