A simple test follows:

Hello, World!

[] = []
[a] = [a]
[abcdef] = [abcdef]
["] = ["]
["""] = ["""]
[a"] = [a"]
["a] = ["a]
[a"b] = [a"b]
[a b] = [a b]
['] = [']
[a'a] = [a'a]
["'  <&>]
[ A]
[śzś]
[ČzČ]

[] = []
[a] = [a]
[abcdef] = [abcdef]
["] = ["]
["""] = ["""]
[a"] = [a"]
["a] = ["a]
[a"b] = [a"b]
[a b] = [a b]
['] = [']
[a'a] = [a'a]
["'  <&>]
[ A]
[śzś]
[ČzČ]