Upgrade to scalatest 3.1.0

[kailuowang]

Scalatest 3.1.0 is yet to be released.
We need to upgrade this to avoid potential compatibility issue with scalacheck 1.14 before we can release 2.0

[erwan]

Do we have visibility on scalatest roadmap? Scalatest 3.1.0 is still not released, should this ticket still block cats 2.0?

[kailuowang]

Due to compatibility with scalacheck on Scala 2.13
, Cats-testkit has to depend on scalatest 3.1.0 . I am on my vacation ATM. I will try find a solution to unblock later this week.

[nafg]

Here's the "countdown": scalatest/scalatest#1656

[julienrf]

Cats-testkit has to depend on scalatest 3.1.0

May I ask what is the reason for that? In #2806 it doesn’t seem that testkit relies on a specific feature of 3.1.0.

Scalatest 3.0.8 is now available for Scala 2.13.0, so it should be possible to revert #2806 and still get 2.13 support.

[kailuowang]

@julienrf
The reason is Scalacheck. Scalatest 3.0.x doesn't support Scalacheck 1.14 which is the only Scalacheck version that supports Scala 2.13.
I am on vacation right now. But if anyone has the time to extract the scalatest dependent part from cats testkit out to a separate module and set it to be not published, and upstate the document teaching people how to integrate with scalatest themselves, I think I can find time to review and help release (or other maintainers can do too).
I will be back Aug 5

[nafg]

So then how were cats 2.0-M4 and scalatest 3.0.8 built for scala 2.13?

[nafg]

Also, what's stopping an earlier version of scalacheck from being published for scala 2.13?