{"_12345", 0, 0, ErrSyntax},
	{"1__2345", 0, 0, ErrSyntax},
	{"12345_", 0, 0, ErrSyntax},

	{"1_2_3_4_5", 10, 0, ErrSyntax}, // base 10
	{"_12345", 10, 0, ErrSyntax},
	{"1__2345", 10, 0, ErrSyntax},
	{"12345_", 10, 0, ErrSyntax},

	{"0x_1_2_3_4_5", 0, 0x12345, nil}, // base 0 => 16
	{"_0x12345", 0, 0, ErrSyntax},
	{"0x__12345", 0, 0, ErrSyntax},
	{"0x1__2345", 0, 0, ErrSyntax},
	{"0x1234__5", 0, 0, ErrSyntax},

		}
	}
}

type encodeTest struct {
	in  []rune
	out []uint16
}

var encodeTests = []encodeTest{
	{[]rune{1, 2, 3, 4}, []uint16{1, 2, 3, 4}},
	{[]rune{0xffff, 0x10000, 0x10001, 0x12345, 0x10ffff},
		[]uint16{0xffff, 0xd800, 0xdc00, 0xd800, 0xdc01, 0xd808, 0xdf45, 0xdbff, 0xdfff}},
	{[]rune{'a', 'b', 0xd7ff, 0xd800, 0xdfff, 0xe000, 0x110000, -1},
		[]uint16{'a', 'b', 0xd7ff, 0xfffd, 0xfffd, 0xe000, 0xfffd, 0xfffd}},

		{"0MiB", 0, true},
		{"0GiB", 0, true},
		{"0TiB", 0, true},

		// Bad inputs.
		{"", 0, false},
		{"-1", 0, false},
		{"a12345", 0, false},
		{"a12345B", 0, false},
		{"12345x", 0, false},
		{"0x12345", 0, false},

		// Bad numeric inputs.
		{"9223372036854775808", 0, false},
		{"9223372036854775809", 0, false},
		{"18446744073709551615", 0, false},
		{"20496382327982653440", 0, false},