add test

Author: pjfanning

Diff for: actor-tests/src/test/scala/org/apache/pekko/util/RandomNumberGeneratorSpec.scala

@@ -0,0 +1,32 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.pekko.util
+
+import org.scalatest.matchers.should.Matchers
+import org.scalatest.wordspec.AnyWordSpec
+
+class RandomNumberGeneratorSpec extends AnyWordSpec with Matchers {
+
+  "RandomNumberGenerator" should {
+
+    "default to ThreadLocalRandom" in {
+      RandomNumberGenerator.get() shouldEqual ThreadLocalRandomNumberGenerator
+    }
+
+  }
+}

Diff for: actor/src/main/resources/reference.conf

@@ -1399,6 +1399,7 @@ pekko {
   random {
     # The default random number generator used by the Pekko library.
     # This setting does not affect SecureRandom use cases.
+    # This option is ignored if you are not using Java 17+. The default is "ThreadLocalRandom".
     # Valid options are listed in
     # https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/random/package-summary.html#algorithms
     generator-implementation = "ThreadLocalRandom"