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Scala Issue with Mixin Traits and Conflicting Members

I have the following setup for ms Scala test where I have a trait that looks like this:

trait CPODBTestContainerSpec extends AnyFlatSpecLike with TestContainerForAll {

  ....
  ....
}

abstract class BaseCPOControllerSpec extends PlaySpec with Results with FakeApplicationFactory with CPODBTestContainerSpec {

  ....
  ....
}

When I tried to run it, I get the following error message. I clearly understand what it states, but I'm not sure how I could fix this. These two traits above do different things and I need both of them in my scope.

class BaseCPOControllerSpec inherits conflicting members:
  protected def info: org.scalatest.Informer (defined in trait AnyWordSpecLike) and
  protected def info: org.scalatest.Informer (defined in trait AnyFlatSpecLike)
  (note: this can be resolved by declaring an `override` in class BaseCPOControllerSpec.);
 other members with override errors are: note, alert, markup, registerTest, registerIgnoredTest, it, they, behave, styleName
abstract class BaseCPOControllerSpec extends PlaySpec with Results with FakeApplicationFactory with CPODBTestContainerSpec {

I learnt about trait linearization, but not sure if I can fix this by restructuring my traits?

Solution

  • The conflict comes from the fact that the hierarchy of traits you want to use is mixing:

    • AnyFlatSpecLike from your own CPODBTestContainerSpec
    • AnyWordSpecLike from PlaySpec

    These are two different ways of writing tests with Scalatest. It doesn't make sense to want to use both.

    If you need the PlaySpec, I would change CPODBTestContainerSpec to extends AnyWordSpecLike.