Add length option for random string provider

[bhagenbourger]

#18

[bhagenbourger]

I added the "length" option that accepts constant and range.
Range must be specified like that : "3..20"
Constant must be specified like that : "8"

I'm not completely satisfied by this solution because the constant must be between double quotes. If an integer is specified the function column["length"].as_str() returns None.

@vianneybacoup do you know a better solution to be able to specify an integer or a string for the constant length?

Thank you for your help.

[vianneybacoup]

Thanks for the range idea @bhagenbourger, it would be a great fit for the random integer min/max as well !

An easy fix would be to cast the integer to str before the .map(), with a match to handle both types. I am not a fan of this solution but it's still better than having to put the quotes in the config file.
Having a dedicated logic for parameters (IntegerParam, RangeParam, DateParam, etc...) to avoid duplicating the logic would be a great enhancement and may be a clean fix for this "issue". But that's an extra feature/refactoring, I'll might do that in the next weeks.

Also the quotes for "5..15" in the yaml file are not necessary :)

[bhagenbourger]

Thank you @vianneybacoup for your help, with pattern matching I was able to solve my issue. Length option can now be specified into the yaml without double quotes.
Agree with you about "Having a dedicated logic for parameters", I let this point for a specific issue.
I also modified tests/tests.rs to manage unix OS. I was able to test only on macos, I hope I didn't break anything on Windows.

[vianneybacoup]

Thanks for this PR as well @bhagenbourger :)