buf = NewReaderSize(dataAndEOFReader("abcd"), 32)
	if s, err := buf.Peek(2); string(s) != "ab" || err != nil {
		t.Errorf(`Peek(2) on "abcd", EOF = %q, %v; want "ab", nil`, string(s), err)
	}
	if s, err := buf.Peek(4); string(s) != "abcd" || err != nil {
		t.Errorf(`Peek(4) on "abcd", EOF = %q, %v; want "abcd", nil`, string(s), err)
	}
	if n, err := buf.Read(p[0:5]); string(p[0:n]) != "abcd" || err != nil {

		{"DATA", "·D(SB)/5,$0.0", "bad float size for DATA argument: 5"},
		{"DATA", "·E(SB)/4,$·A(SB)", "bad addr size for DATA argument: 4"},
		{"DATA", "·F(SB)/8,$·A(SB)", ""},
		{"DATA", "·G(SB)/5,$\"abcde\"", ""},
		{"GLOBL", "", "expect two or three operands for GLOBL"},
		{"GLOBL", "0,1", "GLOBL symbol \"<erroneous symbol>\" must be a symbol(SB)"},
		{"GLOBL", "@B(SB), 0", "expected '(', found B"}, // Issue 23580.

//	}
	MOVW	$1, R1
	MOVW	$foo(SB), R1
	MOVV	$1, R1
	MOVV	$foo(SB), R1

//
// floating point operate
//
//	LFCONV freg ',' freg
//	{
//		outcode(int($1), &$2, 0, &$4);
//	}
	ABSD	F1, F2

//	LFADD freg ',' freg
//	{
//		outcode(int($1), &$2, 0, &$4);
//	}
	ADDD	F1, F2

//	LFADD freg ',' freg ',' freg
//	{
//		outcode(int($1), &$2, int($4.Reg), &$6);
//	}

		wantRes string
		wantKey string
		wantVal string
		ok      bool
	}{
		{"6 k=v\n\n", "\n", "k", "v", true},
		{"19 path=/etc/hosts\n", "", "path", "/etc/hosts", true},
		{"210 path=" + longName + "\nabc", "abc", "path", longName, true},
		{"110 path=" + medName + "\n", "", "path", medName, true},
		{"9 foo=ba\n", "", "foo", "ba", true},
		{"11 foo=bar\n\x00", "\x00", "foo", "bar", true},

string_lit             = raw_string_lit | interpreted_string_lit .
raw_string_lit         = "`" { unicode_char | newline } "`" .
interpreted_string_lit = `"` { unicode_value | byte_value } `"` .
</pre>

<pre>
`abc`                // same as "abc"
`\n
\n`                  // same as "\\n\n\\n"
"\n"
"\""                 // same as `"`
"Hello, world!\n"
"日本語"
"\u65e5本\U00008a9e"
"\xff\u00FF"

	s   string
	sep string
	n   int
	a   []string
}

var splittests = []SplitTest{
	{"", "", -1, []string{}},
	{abcd, "a", 0, nil},
	{abcd, "", 2, []string{"a", "bcd"}},
	{abcd, "a", -1, []string{"", "bcd"}},
	{abcd, "z", -1, []string{"abcd"}},
	{abcd, "", -1, []string{"a", "b", "c", "d"}},
	{commas, ",", -1, []string{"1", "2", "3", "4"}},
	{dots, "...", -1, []string{"1", ".2", ".3", ".4"}},

		tests: []testFnc{
			testReadFrom{fileOps{"ab", int64(3), "cde"}, 7, errMissData},
			testRemaining{1, 0},
		},
	}, {
		maker: makeSparse{makeReg{6, "abcde"}, sparseHoles{{2, 3}}, 8},
		tests: []testFnc{
			testReadFrom{fileOps{"ab", int64(3), "cde"}, 8, errUnrefData},
			testRemaining{0, 1},
		},
	}, {

	const keep = 10
	ss := &suffixSaver{keep: keep}
	ss.Write([]byte("abc"))
	if got := string(ss.Suffix()); got != "abc" {
		t.Errorf("got = %q; want abc", got)
	}
	ss.Write([]byte("defghijklmno"))
	if got := string(ss.Suffix()); got != "fghijklmno" {
		t.Errorf("got = %q; want fghijklmno", got)
	}
	if got, want := ss.Size(), int64(len("abc")+len("defghijklmno")); got != want {
		t.Errorf("Size = %d; want %d", got, want)

		t.Errorf("behavior differs: with = %#v; without: %#v", with, withOut)
	}
}

// tests that Len is affected by reads, but Size is not.
func TestReaderLenSize(t *testing.T) {
	r := NewReader([]byte("abc"))
	io.CopyN(io.Discard, r, 1)
	if r.Len() != 2 {
		t.Errorf("Len = %d; want 2", r.Len())
	}
	if r.Size() != 3 {
		t.Errorf("Size = %d; want 3", r.Size())
	}
}

func TestReaderReset(t *testing.T) {

string_lit             = raw_string_lit | interpreted_string_lit .
raw_string_lit         = "`" { unicode_char | newline } "`" .
interpreted_string_lit = `"` { unicode_value | byte_value } `"` .
</pre>

<pre>
`abc`                // same as "abc"
`\n
\n`                  // same as "\\n\n\\n"
"\n"
"\""                 // same as `"`
"Hello, world!\n"
"日本語"
"\u65e5本\U00008a9e"
"\xff\u00FF"