From 4a2e12c3485f8cf409ed70e322430083c19e4afc Mon Sep 17 00:00:00 2001
From: Guillaume Polaert <gpolaert@gmail.com>
Date: Mon, 14 Aug 2017 14:00:01 +0200
Subject: [PATCH] Test concurrency

---
 .../trace/writer/WriterQueueTest.groovy       | 102 ++++++++++++++++++
 1 file changed, 102 insertions(+)

diff --git a/dd-trace/src/test/groovy/com/datadoghq/trace/writer/WriterQueueTest.groovy b/dd-trace/src/test/groovy/com/datadoghq/trace/writer/WriterQueueTest.groovy
index db703b895b..b5fd656863 100644
--- a/dd-trace/src/test/groovy/com/datadoghq/trace/writer/WriterQueueTest.groovy
+++ b/dd-trace/src/test/groovy/com/datadoghq/trace/writer/WriterQueueTest.groovy
@@ -2,6 +2,9 @@ package com.datadoghq.trace.writer
 
 import spock.lang.Specification
 
+import java.util.concurrent.Phaser
+import java.util.concurrent.atomic.AtomicInteger
+
 class WriterQueueTest extends Specification {
 
   def "instantiate a empty queue throws an exception"() {
@@ -78,4 +81,103 @@ class WriterQueueTest extends Specification {
 
   }
 
+  def "check concurrency on writes"() {
+    setup:
+
+    def phaser_1 = new Phaser()
+    def phaser_2 = new Phaser()
+    def queue = new WriterQueue<Integer>(capacity)
+    def insertionCount = new AtomicInteger(0)
+
+    phaser_1.register() // global start
+    phaser_2.register() // global stop
+
+    numberThreads.times {
+      phaser_1.register()
+      Thread.start {
+        phaser_2.register()
+        phaser_1.arriveAndAwaitAdvance()
+        numberInsertionsPerThread.times {
+          queue.add(1)
+          insertionCount.getAndIncrement()
+        }
+        phaser_2.arriveAndAwaitAdvance()
+      }
+    }
+
+    when:
+    phaser_1.arriveAndAwaitAdvance() // allow threads to start
+    phaser_2.arriveAndAwaitAdvance() // wait till the job is not finished
+
+    then:
+    queue.size() == capacity
+    insertionCount.get() == numberInsertionsPerThread * numberThreads
+
+    where:
+    capacity = 100
+    numberThreads << [1, 10, 100]
+    numberInsertionsPerThread = 100
+
+  }
+
+
+  def "check concurrency on writes and reads"() {
+    setup:
+    def phaser_1 = new Phaser()
+    def phaser_2 = new Phaser()
+    def queue = new WriterQueue<Integer>(capacity)
+    def insertionCount = new AtomicInteger(0)
+    def droppedCount = new AtomicInteger(0)
+    def getCount = new AtomicInteger(0)
+    def numberElements = new AtomicInteger(0)
+
+    phaser_1.register() // global start
+    phaser_2.register() // global stop
+
+    // writes
+    numberThreadsWrites.times {
+      phaser_1.register()
+      Thread.start {
+        phaser_2.register()
+        phaser_1.arriveAndAwaitAdvance()
+        numberInsertionsPerThread.times {
+          queue.add(1) != null ? droppedCount.getAndIncrement() : null
+          insertionCount.getAndIncrement()
+        }
+        phaser_2.arriveAndAwaitAdvance()
+      }
+    }
+
+    // reads
+    numberThreadsReads.times {
+      phaser_1.register()
+      Thread.start {
+        phaser_2.register()
+        phaser_1.arriveAndAwaitAdvance()
+        numberGetsPerThread.times {
+          numberElements.getAndAdd(queue.getAll().size())
+          getCount.getAndIncrement()
+        }
+        phaser_2.arriveAndAwaitAdvance()
+      }
+    }
+
+    when:
+    phaser_1.arriveAndAwaitAdvance() // allow threads to start
+    phaser_2.arriveAndAwaitAdvance() // wait till the job is not finished
+
+    then:
+    insertionCount.get() == numberInsertionsPerThread * numberThreadsWrites
+    getCount.get() == numberGetsPerThread * numberThreadsReads
+    insertionCount.get() == numberElements + queue.size() + droppedCount
+
+    where:
+    capacity = 100
+    numberThreadsWrites << [1, 10, 100]
+    numberThreadsReads << [1, 5, 10]
+    numberInsertionsPerThread = 100
+    numberGetsPerThread = 5
+
+  }
+
 }