Second attempt to fix flaky test

Not sure why these two specs fail, maybe because of the different execution context based on Pekko?

integration-tests/src/test/scala/eu/ostrzyciel/jelly/integration_tests/CrossStreamingSpec.scala

@@ -10,6 +10,7 @@ import org.apache.jena.sparql.util.IsoMatcher
 import org.apache.jena.sys.JenaSystem
 import org.apache.pekko.actor.ActorSystem
 import org.apache.pekko.stream.scaladsl.*
+import org.scalatest.BeforeAndAfterAll
 import org.scalatest.concurrent.ScalaFutures
 import org.scalatest.matchers.should.Matchers
 import org.scalatest.wordspec.AnyWordSpec
@@ -20,12 +21,13 @@ import scala.concurrent.ExecutionContext
 import scala.concurrent.duration.*
 import scala.jdk.CollectionConverters.*
 
-class CrossStreamingSpec extends AnyWordSpec, Matchers, ScalaFutures:
+class CrossStreamingSpec extends AnyWordSpec, Matchers, ScalaFutures, BeforeAndAfterAll:
   implicit val actorSystem: ActorSystem = ActorSystem()
   implicit val ec: ExecutionContext = actorSystem.getDispatcher
   implicit val defaultPatience: PatienceConfig = PatienceConfig(timeout = 5.seconds, interval = 50.millis)
-
-  JenaSystem.init()
+
+  override def beforeAll(): Unit =
+    JenaSystem.init()
 
   private val implementations: Seq[(String, TestStream)] = Seq(
     ("Jena", JenaTestStream),

integration-tests/src/test/scala/eu/ostrzyciel/jelly/integration_tests/io/IoSerDesSpec.scala

@@ -4,6 +4,7 @@ import eu.ostrzyciel.jelly.core.JellyOptions
 import eu.ostrzyciel.jelly.core.proto.v1.RdfStreamOptions
 import org.apache.jena.sys.JenaSystem
 import org.apache.pekko.actor.ActorSystem
+import org.scalatest.BeforeAndAfterAll
 import org.scalatest.concurrent.ScalaFutures
 import org.scalatest.matchers.should.Matchers
 import org.scalatest.wordspec.AnyWordSpec
@@ -13,10 +14,11 @@ import java.io.{ByteArrayInputStream, ByteArrayOutputStream, File, FileInputStre
 /**
  * Tests for IO ser/des (Jena RIOT, RDF4J Rio, and semi-reactive IO over Pekko Streams).
  */
-class IoSerDesSpec extends AnyWordSpec, Matchers, ScalaFutures:
+class IoSerDesSpec extends AnyWordSpec, Matchers, ScalaFutures, BeforeAndAfterAll:
   implicit val as: ActorSystem = ActorSystem("test")
 
-  JenaSystem.init()
+  override def beforeAll(): Unit =
+    JenaSystem.init()
 
   val casesTriples: Seq[(String, File)] = Seq[String](
     "weather.nt", "p2_ontology.nt", "nt-syntax-subm-01.nt", "rdf-star.nt", "rdf-star-blanks.nt"