test: added more testcases

[Pumuckl4630]

No description provided.

[phorward]

Hello @Pumuckl0x520,

first of all, thanks for providing so many test cases.

Can you generally please enhance your testcases to the following:

1. Try to focus onto a topic for a set of testcases. E.g. operators, variable conversions or calculations.

2. Many of your examples calculate something, but then just compare the result. It would be nice to first calculate, check results, and afterwards do several tests with these values.

   Here's an example:

   #SET:hund:"Hund" + "Leine"
   hund
   #EXPECT:"HundLeine"
   #SET:katze:"Katze" + "Fisch"
   katze
   #EXPECT:"KatzeFisch"
   hund == katze
   #EXPECT:False
   hund == hund
   #EXPECT:True
   hund > katze
   #EXPECT:False
   hund < katze
   #EXPECT:True
   

   Be creative with these tests!

3. Please try to avoid using german identifiers and values, so dog and cat would be better.

4. You can name files to optimally describe the topic they are investigating. Here's an example test suite you might use for inspiration: https://github.com/tokay-lang/tokay/tree/main/tests, e.g. there could be a str.lgx, str_len.lgx, str_upper.lgx etc.

[phorward]

@Pumuckl4630 Thanks for your Pull Request! We merge this now and continue on main further on.