{"☺a", 'a', 3},
		{"a☻☺b", '☺', 4},

		// RuneError should match any invalid UTF-8 byte sequence.
		{"�", '�', 0},
		{"\xff", '�', 0},
		{"☻x�", '�', len("☻x")},
		{"☻x\xe2\x98", '�', len("☻x")},
		{"☻x\xe2\x98�", '�', len("☻x")},
		{"☻x\xe2\x98x", '�', len("☻x")},

		// Invalid rune values should never match.
		{"a☺b☻c☹d\xe2\x98�\xff�\xed\xa0\x80", -1, -1},