If you are dealing with software that handles user created file names you should always test your program with names containing several different unicode characters from different character sets.
Special URI Characters
Also, there are some characters that are special characters in the URI specification. For me, these special characters are the reserved characters :/?#@!$&'()*+,;= and the unreserved characters which are not alphanumerical or digits -._~.
As URIs and filenames are often used interchangeably, you need also to test with file names containing the special URI characters.
I hope, that you are seeing all the unicode and special characters on your screen like I’ve intended them 😉
Filenames Which Look Like Encoded Uri Characters
And, further, as in some cases file names get URI-encoded and -decoded it is also necessary to test with file names that look like some encoded special URI characters. I mean file names like %25%20.png or %23.png. Especially important are the encoded space %20 and the encoded percent %25.
Zip Archive and Tcl Script
To make your life easier, I have created a zip archive that contains various files with file names and path names with a set of the mentioned special characters that is usually enough for you to test. All the files are the same small plain text file, just named differently.
You can download the set of files here: TestFiles.zip
It may well be that for your testcase you cannot use the tiny txt files in my zip. Maybe you need pngs or jpegs or whatever. For that case, I’ve created a Tcl script with which you can copy a file of yours to all the differently named files.
Download the script here: createTestFiles.zip