PersistentEntityTestDriver improvements

Tests based on PersistentEntityTestDriver present some repetitive idioms like:

• asserting there’s no serialization issues
• asserting every command handler sends a reply

Writing the tests in Java using JUnit there’s a common snippet in an @After method.

Writing tests in Scala (using scalatest) has similar code duplication. In scalatest-based tests in particular Lagom’s testkit could provide ScalaTest fixture traits to remove the duplication and provide default assertions.

Credit: inspired by scalatestplus-play

[PerWiklander]

Sorry, didn’t check the PR first. Looks like your implementation is very much like mine except throwing an exception instead of using test framework specific checks. And nothing is stopping a user from extending your trait into something more test framework specific if one wanted to do so.

[erip]

@PerWiklander There’s an open PR; the issue is that we don’t want to marry this to scalatest, so we can’t depend on those mixins. See the linked PR.