Add support for FreeSpec

[trackiss]

Add a FreeSpecDiscipline that can be used with AnyFreeSpec.

It inherits AnyFreeSpecLike to avoid errors in Scala 3.
If it is unacceptable, or if there is another better way, please help.

[TonioGela]

Thanks @trackiss! I'm definitely not an expert in Scalatest, so can I ask you if you can provide an example (here as a comment) of what's currently possible with 2.13- but not 3?
Will it be possible for you to write a test that leverages this change and runs for all the scala versions we have configured in the build?

[trackiss]

@TonioGela

thanks.

This code works fine in both Scala 2 and Scala 3! That comments refer to extremely limited cases.

It's not impossible to test without extending Any***SpecLike in ScalaTest, but nobody wants to do that.
The other ***SpecDiscipline can cover that limited case, but not FreeSpecDiscipline with Scala 3.

[TonioGela]

@TonioGela

thanks.

This code works fine in both Scala 2 and Scala 3! That comments refer to extremely limited cases.

It's not impossible to test without extending Any***SpecLike in ScalaTest, but nobody wants to do that. The other ***SpecDiscipline can cover that limited case, but not FreeSpecDiscipline with Scala 3.

I see @trackiss. I'd still like to see a test to prove this is right before merging, idk what other maintainers think.