Added multiTreading test for subscribe.

pubnub-kotlin/pubnub-kotlin-impl/src/integrationTest/kotlin/com/pubnub/api/integration/SubscribeIntegrationTests.kt

@@ -24,6 +24,7 @@ import okhttp3.logging.HttpLoggingInterceptor
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertNotNull
 import org.junit.Assert.assertTrue
+import org.junit.Ignore
 import org.junit.Test
 import org.junit.jupiter.api.Timeout
 import java.util.concurrent.CountDownLatch
@@ -804,6 +805,84 @@ class SubscribeIntegrationTests : BaseIntegrationTest() {
         success.listen()
     }
 
+    @Ignore // For manual use only. It takes long time to run.
+    @Test
+    fun useAllEffectiveThreadsAndForEachOneSubscribeToManyChannels() {
+        val threads = mutableListOf<Thread>()
+
+        val channelsList00 = ('a'..'z').map { "0$it" }
+        val channelsList01 = ('a'..'z').map { "1$it" }
+        val channelsList02 = ('a'..'z').map { "2$it" }
+        val channelsList03 = ('a'..'z').map { "3$it" }
+        val channelsList04 = ('a'..'z').map { "4$it" }
+        val channelsList05 = ('a'..'z').map { "5$it" }
+        val channelsList06 = ('a'..'z').map { "6$it" }
+        val channelsList07 = ('a'..'z').map { "7$it" }
+        val channelsList08 = ('a'..'z').map { "8$it" }
+        val channelsList09 = ('a'..'z').map { "9$it" }
+
+        val thread00 = createThread(channelsList00)
+        val thread01 = createThread(channelsList01)
+        val thread02 = createThread(channelsList02)
+        val thread03 = createThread(channelsList03)
+        val thread04 = createThread(channelsList04)
+        val thread05 = createThread(channelsList05)
+        val thread06 = createThread(channelsList06)
+        val thread07 = createThread(channelsList07)
+        val thread08 = createThread(channelsList08)
+        val thread09 = createThread(channelsList09)
+        threads.add(thread00)
+        threads.add(thread01)
+        threads.add(thread02)
+        threads.add(thread03)
+        threads.add(thread04)
+        threads.add(thread05)
+        threads.add(thread06)
+        threads.add(thread07)
+        threads.add(thread08)
+        threads.add(thread09)
+
+        threads.forEach { thread -> thread.start() }
+
+        publishToChannels(channelsList00)
+        publishToChannels(channelsList01)
+        publishToChannels(channelsList02)
+        publishToChannels(channelsList03)
+        publishToChannels(channelsList04)
+        publishToChannels(channelsList05)
+        publishToChannels(channelsList06)
+        publishToChannels(channelsList07)
+        publishToChannels(channelsList08)
+        publishToChannels(channelsList09)
+
+        threads.forEach { thread -> thread.join() }
+
+        Thread.sleep(3000)
+
+        publishToChannels(channelsList00)
+        publishToChannels(channelsList01)
+        publishToChannels(channelsList02)
+        publishToChannels(channelsList03)
+        publishToChannels(channelsList04)
+        publishToChannels(channelsList05)
+        publishToChannels(channelsList06)
+        publishToChannels(channelsList07)
+        publishToChannels(channelsList08)
+        publishToChannels(channelsList09)
+
+        Thread.sleep(3000)
+
+        val allChannelsLists = listOf(
+            channelsList00, channelsList01, channelsList02, channelsList03,
+            channelsList04, channelsList05, channelsList06, channelsList07,
+            channelsList08, channelsList09
+        )
+
+        val channelsFromAllThreads = allChannelsLists.flatten()
+
+        assertEquals(pubnub.getSubscribedChannels().toSet(), channelsFromAllThreads.toSet())
+    }
+
     @Test
     fun testAssigningEventBehaviourToSubscriptionSet() {
         val successMessage = AtomicInteger(0)
@@ -892,4 +971,21 @@ class SubscribeIntegrationTests : BaseIntegrationTest() {
         subscriptionSet -= subscription01
         assertEquals(2, subscriptionSet.subscriptions.size)
     }
+
+    private fun publishToChannels(channelsList: List<String>) {
+        channelsList.forEach { channelName ->
+            pubnub.publish(channelName, "-=message to $channelName").sync()
+        }
+    }
+
+    private fun createThread(channelsList: List<String>) = Thread {
+        channelsList.forEach { channelName ->
+            val chan01 = pubnub.channel(channelName)
+            val sub01 = chan01.subscription()
+            sub01.onMessage = { pnMessageResult: PNMessageResult ->
+                println("-=message: " + pnMessageResult.message + " channel: " + pnMessageResult.channel + " channelName: " + channelName)
+            }
+            sub01.subscribe()
+        }
+    }
 }