{"\u0250\u0250\u0250\u0250\u0250", []byte("\u2C6F\u2C6F\u2C6F\u2C6F\u2C6F")}, // grows one byte per char
	{"a\u0080\U0010FFFF", []byte("A\u0080\U0010FFFF")},                           // test utf8.RuneSelf and utf8.MaxRune
}

var lowerTests = []StringTest{
	{"", []byte("")},
	{"abc", []byte("abc")},
	{"AbC123", []byte("abc123")},