Make ES tests more deterministic by using listener pool with 1 thread

This should reduce number of false negatives in ES tests

dd-java-agent/instrumentation/elasticsearch-transport-2/src/test/groovy/Elasticsearch2NodeClientTest.groovy

@@ -34,6 +34,8 @@ class Elasticsearch2NodeClientTest extends AgentTestRunner {
 
     def settings = Settings.builder()
       .put("path.home", esWorkingDir.path)
+      // Since we use listeners to close spans this should make our span closing deterministic which is good for tests
+      .put("thread_pool.listener.size", 1)
       .put("http.port", HTTP_PORT)
       .put("transport.tcp.port", TCP_PORT)
       .build()

dd-java-agent/instrumentation/elasticsearch-transport-2/src/test/groovy/Elasticsearch2SpringTemplateTest.groovy

@@ -45,6 +45,8 @@ class Elasticsearch2SpringTemplateTest extends AgentTestRunner {
 
     def settings = Settings.builder()
       .put("path.home", esWorkingDir.path)
+      // Since we use listeners to close spans this should make our span closing deterministic which is good for tests
+      .put("thread_pool.listener.size", 1)
       .put("http.port", HTTP_PORT)
       .put("transport.tcp.port", TCP_PORT)
       .build()

dd-java-agent/instrumentation/elasticsearch-transport-2/src/test/groovy/Elasticsearch2TransportClientTest.groovy

@@ -46,6 +46,8 @@ class Elasticsearch2TransportClientTest extends AgentTestRunner {
 
     client = TransportClient.builder().settings(
       Settings.builder()
+        // Since we use listeners to close spans this should make our span closing deterministic which is good for tests
+        .put("thread_pool.listener.size", 1)
         .put("cluster.name", "test-cluster")
         .build()
     ).build()

dd-java-agent/instrumentation/elasticsearch-transport-5/src/test/groovy/Elasticsearch5NodeClientTest.groovy

@@ -37,6 +37,8 @@ class Elasticsearch5NodeClientTest extends AgentTestRunner {
 
     def settings = Settings.builder()
       .put("path.home", esWorkingDir.path)
+      // Since we use listeners to close spans this should make our span closing deterministic which is good for tests
+      .put("thread_pool.listener.size", 1)
       .put("http.port", HTTP_PORT)
       .put("transport.tcp.port", TCP_PORT)
       .put("transport.type", "netty3")

dd-java-agent/instrumentation/elasticsearch-transport-5/src/test/groovy/Elasticsearch5TransportClientTest.groovy

@@ -53,6 +53,8 @@ class Elasticsearch5TransportClientTest extends AgentTestRunner {
 
     client = new PreBuiltTransportClient(
       Settings.builder()
+        // Since we use listeners to close spans this should make our span closing deterministic which is good for tests
+        .put("thread_pool.listener.size", 1)
         .put(CLUSTER_NAME_SETTING.getKey(), "test-cluster")
         .build()
     )

dd-java-agent/instrumentation/elasticsearch-transport-6/src/test/groovy/Elasticsearch6NodeClientTest.groovy

@@ -36,6 +36,8 @@ class Elasticsearch6NodeClientTest extends AgentTestRunner {
 
     def settings = Settings.builder()
       .put("path.home", esWorkingDir.path)
+      // Since we use listeners to close spans this should make our span closing deterministic which is good for tests
+      .put("thread_pool.listener.size", 1)
       .put("http.port", HTTP_PORT)
       .put("transport.tcp.port", TCP_PORT)
       .put(CLUSTER_NAME_SETTING.getKey(), "test-cluster")

dd-java-agent/instrumentation/elasticsearch-transport-6/src/test/groovy/Elasticsearch6TransportClientTest.groovy

@@ -50,6 +50,8 @@ class Elasticsearch6TransportClientTest extends AgentTestRunner {
 
     client = new PreBuiltTransportClient(
       Settings.builder()
+        // Since we use listeners to close spans this should make our span closing deterministic which is good for tests
+        .put("thread_pool.listener.size", 1)
         .put(CLUSTER_NAME_SETTING.getKey(), "test-cluster")
         .build()
     )