// UTF-8-encoded rune as a token. The sequence of runes returned is
// equivalent to that from a range loop over the input as a string, which
// means that erroneous UTF-8 encodings translate to U+FFFD = "\xef\xbf\xbd".
// Because of the Scan interface, this makes it impossible for the client to
// distinguish correctly encoded replacement runes from encoding errors.

		}
	}
}

// Test that the rune splitter returns same sequence of runes (not bytes) as for range string.
func TestScanRune(t *testing.T) {
	for n, test := range scanTests {
		buf := strings.NewReader(test)
		s := NewScanner(buf)
		s.Split(ScanRunes)
		var i, runeCount int
		var expect rune
		// Use a string range loop to validate the sequence of runes.
		for i, expect = range test {
			if !s.Scan() {
				break
			}

		// returning nil instead of empty slice if all spaces.
		return nil
	}
	return s[start:stop]
}

// Runes interprets s as a sequence of UTF-8-encoded code points.
// It returns a slice of runes (Unicode code points) equivalent to s.
func Runes(s []byte) []rune {
	t := make([]rune, utf8.RuneCount(s))
	i := 0
	for len(s) > 0 {
		r, l := utf8.DecodeRune(s)
		t[i] = r
		i++

		}
		if !Equal(actual, tc.out) {
			t.Errorf("%s(%q) = %q; want %q", funcName, tc.in, actual, tc.out)
		}
	}
}

func tenRunes(r rune) string {
	runes := make([]rune, 10)
	for i := range runes {
		runes[i] = r
	}
	return string(runes)
}

// User-defined self-inverse mapping function
func rot13(r rune) rune {
	const step = 13
	if r >= 'a' && r <= 'z' {

			t.Errorf("#%d: got error %v; want EOF", rno, err)
		}
	}
}

// Test that UnreadRune fails if the preceding operation was not a ReadRune.
func TestUnreadRuneError(t *testing.T) {
	buf := make([]byte, 3) // All runes in this test are 3 bytes long
	r := NewReader(&StringReader{data: []string{"日本語日本語日本語"}})
	if r.UnreadRune() == nil {
		t.Error("expected error on UnreadRune from fresh buffer")
	}
	_, _, err := r.ReadRune()

// if it becomes too large, WriteRune will panic with [ErrTooLarge].
func (b *Buffer) WriteRune(r rune) (n int, err error) {
	// Compare as uint32 to correctly handle negative runes.
	if uint32(r) < utf8.RuneSelf {
		b.WriteByte(byte(r))
		return 1, nil
	}
	b.lastRead = opInvalid
	m, ok := b.tryGrowByReslice(utf8.UTFMax)
	if !ok {
		m = b.grow(utf8.UTFMax)
	}

}

// WriteRune writes a single Unicode code point, returning
// the number of bytes written and any error.
func (b *Writer) WriteRune(r rune) (size int, err error) {
	// Compare as uint32 to correctly handle negative runes.
	if uint32(r) < utf8.RuneSelf {
		err = b.WriteByte(byte(r))
		if err != nil {
			return 0, err
		}
		return 1, nil
	}
	if b.err != nil {
		return 0, b.err
	}
	n := b.Available()

}

func ExampleReplaceAll() {
	fmt.Printf("%s\n", bytes.ReplaceAll([]byte("oink oink oink"), []byte("oink"), []byte("moo")))
	// Output:
	// moo moo moo
}

func ExampleRunes() {
	rs := bytes.Runes([]byte("go gopher"))
	for _, r := range rs {
		fmt.Printf("%#U\n", r)
	}
	// Output:
	// U+0067 'g'
	// U+006F 'o'
	// U+0020 ' '
	// U+0067 'g'
	// U+006F 'o'
	// U+0070 'p'
	// U+0068 'h'

			t.Fatalf("ReadRune(%U) after UnreadRune got %U,%d not %U,%d (err=%s)", r, r2, nbytes, r, size, err)
		}
	}
}

func TestWriteInvalidRune(t *testing.T) {
	// Invalid runes, including negative ones, should be written as
	// utf8.RuneError.
	for _, r := range []rune{-1, utf8.MaxRune + 1} {
		var buf Buffer
		buf.WriteRune(r)

	switch {
	case !utf8Valid1 || !utf8Valid2:
		// Name and Comment definitely not UTF-8.
		f.NonUTF8 = true
	case !utf8Require1 && !utf8Require2:
		// Name and Comment use only single-byte runes that overlap with UTF-8.
		f.NonUTF8 = false
	default:
		// Might be UTF-8, might be some other encoding; preserve existing flag.
		// Some ZIP writers use UTF-8 encoding without setting the UTF-8 flag.