diff --git a/build.sbt b/build.sbt
index ece43e07..db852a11 100644
--- a/build.sbt
+++ b/build.sbt
@@ -137,8 +137,8 @@ lazy val zio = project
     name := "colibri-zio",
     libraryDependencies ++= Seq(
       "io.github.cquiroz" %%% "scala-java-time" % "2.5.0",
-      "dev.zio"           %%% "zio"             % "2.0.6",
-      "dev.zio"           %%% "zio-streams"     % "2.0.6",
+      "dev.zio"           %%% "zio"             % "2.0.19",
+      "dev.zio"           %%% "zio-streams"     % "2.0.19",
     ),
   )
 
diff --git a/zio/src/test/scala/colibri/ObservableSpec.scala b/zio/src/test/scala/colibri/ObservableSpec.scala
index 6c9c230b..b5155c81 100644
--- a/zio/src/test/scala/colibri/ObservableSpec.scala
+++ b/zio/src/test/scala/colibri/ObservableSpec.scala
@@ -1,12 +1,23 @@
 package colibri
 
+import cats.effect.IO
+import cats.effect.unsafe
 import zio._
-// import zio.stream.ZStream
 import colibri.ext.zio._
 import org.scalatest.matchers.should.Matchers
 import org.scalatest.flatspec.AsyncFlatSpec
 
+import java.util.concurrent.TimeUnit
+
 class ObservableSpec extends AsyncFlatSpec with Matchers {
+  override val executionContext            = scala.scalajs.concurrent.QueueExecutionContext()
+  implicit val ioRuntime: unsafe.IORuntime = unsafe.IORuntime(
+    compute = this.executionContext,
+    blocking = this.executionContext,
+    config = unsafe.IORuntimeConfig(),
+    scheduler = unsafe.IORuntime.defaultScheduler,
+    shutdown = () => (),
+  )
 
   "Observable" should "recover after mapEffect" in {
     var recovered      = List.empty[Throwable]
@@ -76,8 +87,21 @@ class ObservableSpec extends AsyncFlatSpec with Matchers {
       ),
     )
 
-    received shouldBe List(15, 10, 6, 3, 1, 0)
+    cancelable.isEmpty() shouldBe false
+    received shouldBe List.empty
     errors shouldBe 0
-    cancelable.isEmpty() shouldBe true
+
+    import scala.concurrent.duration._
+
+    val test = for {
+      //TODO: why does it need an actual delay?
+      _ <- IO.sleep(FiniteDuration.apply(1, TimeUnit.SECONDS))
+
+      _ = received shouldBe List(15, 10, 6, 3, 1, 0)
+      _ = errors shouldBe 0
+      _ = cancelable.isEmpty() shouldBe true
+    } yield succeed
+
+    test.unsafeToFuture()
   }
 }