diff --git a/graphql-spring-boot-test/src/main/java/com/graphql/spring/boot/test/GraphQLTestSubscription.java b/graphql-spring-boot-test/src/main/java/com/graphql/spring/boot/test/GraphQLTestSubscription.java
index f52023f4..05b1d02f 100644
--- a/graphql-spring-boot-test/src/main/java/com/graphql/spring/boot/test/GraphQLTestSubscription.java
+++ b/graphql-spring-boot-test/src/main/java/com/graphql/spring/boot/test/GraphQLTestSubscription.java
@@ -47,6 +47,7 @@
 public class GraphQLTestSubscription {
 
     private static final int SLEEP_INTERVAL_MS = 100;
+    private static final int ACKNOWLEDGEMENT_AND_CONNECTION_TIMEOUT = 6000000;
     private static final AtomicInteger ID_COUNTER = new AtomicInteger(1);
     private static final UriBuilderFactory URI_BUILDER_FACTORY = new DefaultUriBuilderFactory();
 
@@ -97,6 +98,7 @@ public GraphQLTestSubscription init(@Nullable final Object payload) {
         message.set("payload", getFinalPayload(payload));
         sendMessage(message);
         initialized = true;
+        awaitAcknowledgement();
         return this;
     }
 
@@ -141,8 +143,8 @@ public GraphQLTestSubscription start(@NonNull final String graphGLResource, @Nul
      * @return self reference
      */
     public GraphQLTestSubscription stop() {
-        if (!started) {
-            fail("Subscription not yet started.");
+        if (!initialized) {
+            fail("Subscription not yet initialized.");
         }
         if (stopped) {
             fail("Subscription already stopped.");
@@ -177,7 +179,10 @@ public void reset() {
         started = false;
         stopped = false;
         acknowledged = false;
-        responses.clear();
+        session = null;
+        synchronized (responses) {
+            responses.clear();
+        }
     }
 
     /**
@@ -348,6 +353,8 @@ private void initClient() throws Exception {
         final ClientEndpointConfig clientEndpointConfig = ClientEndpointConfig.Builder.create()
             .configurator(new TestWebSocketClientConfigurator())
             .build();
+        clientEndpointConfig.getUserProperties().put("org.apache.tomcat.websocket.IO_TIMEOUT_MS",
+            String.valueOf(ACKNOWLEDGEMENT_AND_CONNECTION_TIMEOUT));
         session = webSocketContainer.connectToServer(TestWebSocketClient.class, clientEndpointConfig, uri);
         session.addMessageHandler(new TestMessageHandler());
     }
@@ -376,6 +383,22 @@ private void sendMessage(final Object message) {
         }
     }
 
+    private void awaitAcknowledgement() {
+        int elapsedTime = 0;
+        while(!acknowledged && elapsedTime < ACKNOWLEDGEMENT_AND_CONNECTION_TIMEOUT) {
+            try {
+                Thread.sleep(SLEEP_INTERVAL_MS);
+                elapsedTime += SLEEP_INTERVAL_MS;
+            } catch (InterruptedException e) {
+                fail("Test execution error - Thread.sleep failed.", e);
+            }
+        }
+
+        if (!acknowledged) {
+            fail("Timeout: Connection was not acknowledged by the GraphQL server.");
+        }
+    }
+
     class TestMessageHandler implements MessageHandler.Whole<String> {
         @Override
         public void onMessage(final String message) {
diff --git a/graphql-spring-boot-test/src/test/java/com/graphql/spring/boot/test/GraphQLTestSubscriptionTestBase.java b/graphql-spring-boot-test/src/test/java/com/graphql/spring/boot/test/GraphQLTestSubscriptionTestBase.java
index 9d5a049b..5320a7a8 100644
--- a/graphql-spring-boot-test/src/test/java/com/graphql/spring/boot/test/GraphQLTestSubscriptionTestBase.java
+++ b/graphql-spring-boot-test/src/test/java/com/graphql/spring/boot/test/GraphQLTestSubscriptionTestBase.java
@@ -1,6 +1,7 @@
 package com.graphql.spring.boot.test;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
@@ -37,6 +38,11 @@ protected void setUp() {
         graphQLTestSubscription = new GraphQLTestSubscription(environment, objectMapper, "subscriptions");
     }
 
+    @AfterEach
+    protected void tearDown() {
+        graphQLTestSubscription.reset();
+    }
+
     protected void assertThatSubscriptionStoppedStatusIs(boolean isStopped) {
         if (isStopped) {
             assertThatSubscriptionWasStopped();