wantpos int64
		readerr error
		seekerr string
	}{
		{seek: io.SeekStart, off: 0, n: 20, want: "0123456789"},
		{seek: io.SeekStart, off: 1, n: 1, want: "1"},
		{seek: io.SeekCurrent, off: 1, wantpos: 3, n: 2, want: "34"},
		{seek: io.SeekStart, off: -1, seekerr: "bytes.Reader.Seek: negative position"},
		{seek: io.SeekStart, off: 1 << 33, wantpos: 1 << 33, readerr: io.EOF},
		{seek: io.SeekCurrent, off: 1, wantpos: 1<<33 + 1, readerr: io.EOF},

	{dots, "...", -1, []string{"1", ".2", ".3", ".4"}},
	{faces, "☹", -1, []string{"☺☻", ""}},
	{faces, "~", -1, []string{faces}},
	{faces, "", -1, []string{"☺", "☻", "☹"}},
	{"1 2 3 4", " ", 3, []string{"1", "2", "3 4"}},
	{"1 2", " ", 3, []string{"1", "2"}},
	{"123", "", 2, []string{"1", "23"}},
	{"123", "", 17, []string{"1", "2", "3"}},
	{"bT", "T", math.MaxInt / 4, []string{"b", ""}},

0000290 00 0d d0 00 0d d0 00 0d d0 00 0d d0 00 0d d0 00
00002a0 0d d0 00 cd ff 9e 46 86 fa a7 7d 3a 43 d7 8e 10
00002b0 52 e9 be e6 6e cf eb 9e 85 4d 65 ce cc 30 c1 44
00002c0 c0 4e af bc 9c 6c 4b a0 d7 54 ff 1d d5 5c 89 fb
00002d0 b5 34 7e c4 c2 9e f5 a0 f6 5b 7e 6e ca 73 c7 ef
00002e0 5d be de f9 e8 81 eb a5 0a a5 63 54 2c d7 1c d1
00002f0 89 17 85 f8 16 94 f2 8a b2 a3 f5 b6 6d df 75 cd
0000300 90 dd 64 bd 5d 55 4e f2 55 19 1b b7 cc ef 1b ea

		"0/1/2/3/4/5/6/7/8/9/10/11/12/13/14/15/16/17/18/19/20/21/22/23/24/25/26/27/28/29/30/31/32/333/file.txt",
		"0/1/2/3/4/5/6/7/8/9/10/11/12/13/14/15/16/17/18/19/20/21/22/23/24/25/26/27/28/29/30/31/32/33/34/35/36/37/38/39/40/file.txt",
		"0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000/file.txt",