One way to group tags in ScalaTest 2.0

gistfile1.txt

import org.scalatest._

trait TagGroups extends SuiteMixin { this: Suite =>

    private val groups: Map[String, Set[String]] =
      Map(
        "NonUnit" -> Set("org.scalatest.tags.Disk", "org.scalatest.tags.Network"),
        "Sluggish" -> Set("org.scalatest.tags.Slow", "org.scalatest.tags.Network")
      )

    abstract override def run(testName: Option[String], args: Args): Status = {

      def expandGroups(set: Set[String]): Set[String] = 
        set flatMap { tag => groups.getOrElse(tag, Set(tag)) }

      val newTagsToInclude: Option[Set[String]] =
        for (set <- args.filter.tagsToInclude) yield expandGroups(set)

      val newTagsToExclude: Set[String] = expandGroups(args.filter.tagsToExclude)

      val newFilter: Filter =
        Filter(
          newTagsToInclude,
          newTagsToExclude,
          args.filter.excludeNestedSuites,
          args.filter.dynaTags
        )

      super.run(testName, args.copy(filter = newFilter))
    }
  }