Tool to create and copy special and non-printable character string to Clipboard for testing

I'm looking for a tool (ideally online) that lets me specify a string with special and unprintable character codes (e.g. < Code 32), by code, and copy it to the Clipboard for testing.

There are tools that do the opposite, like this one: https://www.soscisurvey.de/tools/view-chars.php - Here you can paste a string and see what special characters it contains.

I can write a Java program that specifies chars by code, but that's only useful to me as a developer when debugging (e.g. in Eclipse). The testing team needs a way to prepare strings with special chars based on codes, as below, copy them to the Clipboard as rendered strings, and then input them as test data into GUI fields.

String testStr = " ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
            "abcdefghijklmnopqrstuvwxyz" +
            "1234567890" +
            "`~!@#$%^&*()-_=+" +
            "[]
{}|" +
            ";':\"" +
            ",./<>?" +
            "\r\n" + // CARRIAGE RETURN, LINE FEED
            "\u00e1" + //     e1 //    0x00E1    225    LATIN SMALL LETTER A WITH ACUTE
            "\u00e9" + //     e9 //   0x00E9    233    LATIN SMALL LETTER E WITH ACUTE
            "\u00ed" + //     ed //   0x00ED    237    LATIN SMALL LETTER I WITH ACUTE
            "\u00f3" + //     f3 //   0x00F3    243    LATIN SMALL LETTER O WITH ACUTE
            "\u00fa" + //     fa //    0x00FA    250    LATIN SMALL LETTER U WITH ACUTE
            "\u00fc" + //     fc //    0x00FC    252    LATIN SMALL LETTER U WITH DIAERESIS
            "\u00f1" + //     f1 //    0x00F1    241    LATIN SMALL LETTER N WITH TILDE
            "\u00c1" + //     c1 //    0x00C1    193    LATIN CAPITAL LETTER A WITH ACUTE
            "\u00c9" + //     c9 //    0x00C9    201    LATIN CAPITAL LETTER E WITH ACUTE
            "\u00cd" + //     cd //    0x00CD    205    LATIN CAPITAL LETTER I WITH ACUTE
            "\u00d3" + //     d3 //    0x00D3    211    LATIN CAPITAL LETTER O WITH ACUTE
            "\u00da" + //     da //    0x00DA    218    LATIN CAPITAL LETTER U WITH ACUTE
            "\u00dc" + //     dc //    0x00DC    220    LATIN CAPITAL LETTER U WITH DIAERESIS
            "\u00d1" + //     d1 //    0x00D1    209    LATIN CAPITAL LETTER N WITH TILDE
            "\u00bf" + //     bf //    0x00BF    191    INVERTED QUESTION MARK
            "\u00a1"; //     a1 //   0x00A1    161    INVERTED EXCLAMATION MARK) 

Also, I can't just copy rendered symbols from various online listings of character codes, since unprintable chars < Code 32 will be masked by the browser. I've looked into Notepad++ plugins, but they're also not that straightforward. In Notepad++, I can type Alt+[Code] to insert a special character, but anything <32 will be masked and I can't copy it for my purposes.

I also found a Notepad++ solution. Click Edit -> Character Panel. From the character panel, double-click in the 3rd column the special char you want to insert.

CyberChef seems like a tool you could use. It has an online version here or you can grab it via sources from github. It's a swiss army knife for text processing (encoding, decoding, deciphering). For your use case select From Charcode from operations and use base 10.

I was able to copy the non-printables to Notepad ++ with it.