var scanTests = []string{
	"",
	"a",
	"¼",
	"☹",
	"\x81",   // UTF-8 error
	"\uFFFD", // correctly encoded RuneError
	"abcdefgh",
	"abc def\n\t\tgh    ",
	"abc¼☹\x81\uFFFD日本語\x82abc",
}

func TestScanByte(t *testing.T) {
	for n, test := range scanTests {
		buf := strings.NewReader(test)
		s := NewScanner(buf)
		s.Split(ScanBytes)
		var i int
		for i = 0; s.Scan(); i++ {