Add SocketAllocationSpec

bridge/src/test/scala/protocbridge/frontend/SocketAllocationSpec.scala

@@ -0,0 +1,50 @@
+package protocbridge.frontend
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.must.Matchers
+
+import java.lang.management.ManagementFactory
+import java.net.ServerSocket
+import scala.collection.mutable
+import scala.sys.process._
+import scala.util.{Failure, Success, Try}
+
+class SocketAllocationSpec extends AnyFlatSpec with Matchers {
+  it must "allocate an unused port" in {
+    val repeatCount = 100000
+    val portConflictCount = mutable.Map[Int, Int]()
+
+    val currentPid = getCurrentPid
+
+    for (i <- 1 to repeatCount) {
+      if (i % 100 == 1) println(s"Running iteration $i of $repeatCount")
+
+      val serverSocket = new ServerSocket(0) // Bind to any available port.
+      try {
+        val port = serverSocket.getLocalPort
+        Try {
+          s"lsof -i :$port -t".!!.trim
+        } match {
+          case Success(output) =>
+            if (output.nonEmpty) {
+              val pids = output.split("\n").filterNot(_.contains(currentPid.toString))
+              if (pids.nonEmpty) {
+                System.err.println("Port conflict detected on port " + port + " with PIDs: " + pids.mkString(", "))
+                portConflictCount(port) = portConflictCount.getOrElse(port, 0) + 1
+              }
+            }
+          case Failure(_) => // Ignore failure and continue
+        }
+      } finally {
+        serverSocket.close()
+      }
+    }
+
+    assert(portConflictCount.isEmpty, s"Found the following ports in use out of $repeatCount: $portConflictCount")
+  }
+
+  private def getCurrentPid: Int = {
+    val jvmName = ManagementFactory.getRuntimeMXBean.getName
+    val pid = jvmName.split("@")(0)
+    pid.toInt
+  }
+}