diff --git a/core/pom.xml b/core/pom.xml
index d7cee0c16..71a3f777b 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -339,8 +339,7 @@
         <dependency>
             <groupId>org.testng</groupId>
             <artifactId>testng</artifactId>
-            <scope>compile</scope>
-            <optional>true</optional>
+            <scope>test</scope>
         </dependency>
 
         <!-- SLF4J support -->
diff --git a/core/src/test/java/org/apache/struts2/dispatcher/multipart/JakartaStreamMultiPartRequestTest.java b/core/src/test/java/org/apache/struts2/dispatcher/multipart/JakartaStreamMultiPartRequestTest.java
index cf453acac..59861e2ed 100644
--- a/core/src/test/java/org/apache/struts2/dispatcher/multipart/JakartaStreamMultiPartRequestTest.java
+++ b/core/src/test/java/org/apache/struts2/dispatcher/multipart/JakartaStreamMultiPartRequestTest.java
@@ -18,53 +18,50 @@
  */
 package org.apache.struts2.dispatcher.multipart;
 
+import org.apache.struts2.dispatcher.LocalizedMessage;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mockito;
+import org.springframework.mock.web.DelegatingServletInputStream;
+
+import javax.servlet.http.HttpServletRequest;
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 
-import javax.servlet.http.HttpServletRequest;
-
-import org.apache.struts2.dispatcher.LocalizedMessage;
-import org.junit.Before;
-import org.junit.Test;
-import org.mockito.Mockito;
-import org.springframework.mock.web.DelegatingServletInputStream;
-import org.testng.Assert;
-
 public class JakartaStreamMultiPartRequestTest {
 
     private JakartaStreamMultiPartRequest multiPart;
     private Path tempDir;
-    
+
     @Before
     public void initialize() {
         multiPart = new JakartaStreamMultiPartRequest();
         tempDir = Paths.get("target", "multi-part-test");
     }
-    
+
     /**
      * Number of bytes in files greater than 2GB overflow the {@code int} primative.
-     * The {@link HttpServletRequest#getContentLength()} returns {@literal -1} 
+     * The {@link HttpServletRequest#getContentLength()} returns {@literal -1}
      * when the header is not present or the size is greater than {@link Integer#MAX_VALUE}.
-     * @throws IOException 
      */
     @Test
     public void unknownContentLength() throws IOException {
         HttpServletRequest request = Mockito.mock(HttpServletRequest.class);
         Mockito.when(request.getContentType()).thenReturn("multipart/form-data; charset=utf-8; boundary=__X_BOUNDARY__");
         Mockito.when(request.getMethod()).thenReturn("POST");
-        Mockito.when(request.getContentLength()).thenReturn(Integer.valueOf(-1));
-        StringBuilder entity = new StringBuilder();
-        entity.append("\r\n--__X_BOUNDARY__\r\n");
-        entity.append("Content-Disposition: form-data; name=\"upload\"; filename=\"test.csv\"\r\n");
-        entity.append("Content-Type: text/csv\r\n\r\n1,2\r\n\r\n");
-        entity.append("--__X_BOUNDARY__\r\n");
-        entity.append("Content-Disposition: form-data; name=\"upload2\"; filename=\"test2.csv\"\r\n");
-        entity.append("Content-Type: text/csv\r\n\r\n3,4\r\n\r\n");
-        entity.append("--__X_BOUNDARY__--\r\n");
-        Mockito.when(request.getInputStream()).thenReturn(new DelegatingServletInputStream(new ByteArrayInputStream(entity.toString().getBytes(StandardCharsets.UTF_8))));
+        Mockito.when(request.getContentLength()).thenReturn(-1);
+        String entity = "\r\n--__X_BOUNDARY__\r\n" +
+            "Content-Disposition: form-data; name=\"upload\"; filename=\"test.csv\"\r\n" +
+            "Content-Type: text/csv\r\n\r\n1,2\r\n\r\n" +
+            "--__X_BOUNDARY__\r\n" +
+            "Content-Disposition: form-data; name=\"upload2\"; filename=\"test2.csv\"\r\n" +
+            "Content-Type: text/csv\r\n\r\n3,4\r\n\r\n" +
+            "--__X_BOUNDARY__--\r\n";
+        Mockito.when(request.getInputStream()).thenReturn(new DelegatingServletInputStream(new ByteArrayInputStream(entity.getBytes(StandardCharsets.UTF_8))));
         multiPart.setMaxSize("4");
         multiPart.parse(request, tempDir.toString());
         LocalizedMessage next = multiPart.getErrors().iterator().next();
diff --git a/plugins/testng/pom.xml b/plugins/testng/pom.xml
index 823941ba1..cc4d2ba51 100644
--- a/plugins/testng/pom.xml
+++ b/plugins/testng/pom.xml
@@ -35,7 +35,6 @@
         <dependency>
             <groupId>org.testng</groupId>
             <artifactId>testng</artifactId>
-            <version>6.9.10</version>
         </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
diff --git a/plugins/testng/src/main/java/org/apache/struts2/StrutsTestCase.java b/plugins/testng/src/main/java/org/apache/struts2/testng/StrutsTestCase.java
similarity index 96%
rename from plugins/testng/src/main/java/org/apache/struts2/StrutsTestCase.java
rename to plugins/testng/src/main/java/org/apache/struts2/testng/StrutsTestCase.java
index 193f14220..630eb2df6 100644
--- a/plugins/testng/src/main/java/org/apache/struts2/StrutsTestCase.java
+++ b/plugins/testng/src/main/java/org/apache/struts2/testng/StrutsTestCase.java
@@ -16,7 +16,7 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-package org.apache.struts2;
+package org.apache.struts2.testng;
 
 import java.util.Map;
 
@@ -26,8 +26,6 @@ import org.testng.annotations.AfterTest;
 import org.testng.annotations.BeforeTest;
 import org.springframework.mock.web.MockServletContext;
 
-import com.opensymphony.xwork2.TestNGXWorkTestCase;
-
 /**
  * Base test class for TestNG unit tests.  Provides common Struts variables
  * and performs Struts setup and teardown processes
@@ -39,7 +37,7 @@ public class StrutsTestCase extends TestNGXWorkTestCase {
         super.setUp();
         initDispatcher(null);
     }
-    
+
     protected Dispatcher initDispatcher(Map<String,String> params) {
         Dispatcher du = StrutsTestCaseHelper.initDispatcher(new MockServletContext(), params);
         configurationManager = du.getConfigurationManager();
diff --git a/core/src/main/java/com/opensymphony/xwork2/TestNGXWorkTestCase.java b/plugins/testng/src/main/java/org/apache/struts2/testng/TestNGXWorkTestCase.java
similarity index 96%
rename from core/src/main/java/com/opensymphony/xwork2/TestNGXWorkTestCase.java
rename to plugins/testng/src/main/java/org/apache/struts2/testng/TestNGXWorkTestCase.java
index 3f34dfec1..3d3519b3d 100644
--- a/core/src/main/java/com/opensymphony/xwork2/TestNGXWorkTestCase.java
+++ b/plugins/testng/src/main/java/org/apache/struts2/testng/TestNGXWorkTestCase.java
@@ -16,8 +16,9 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-package com.opensymphony.xwork2;
+package org.apache.struts2.testng;
 
+import com.opensymphony.xwork2.ActionProxyFactory;
 import com.opensymphony.xwork2.config.Configuration;
 import com.opensymphony.xwork2.config.ConfigurationManager;
 import com.opensymphony.xwork2.config.ConfigurationProvider;
diff --git a/plugins/testng/src/test/java/org/apache/struts2/TestNGStrutsTestCaseTest.java b/plugins/testng/src/test/java/org/apache/struts2/testng/TestNGStrutsTestCaseTest.java
similarity index 95%
rename from plugins/testng/src/test/java/org/apache/struts2/TestNGStrutsTestCaseTest.java
rename to plugins/testng/src/test/java/org/apache/struts2/testng/TestNGStrutsTestCaseTest.java
index dd4ab6a7a..cd86bf99c 100644
--- a/plugins/testng/src/test/java/org/apache/struts2/TestNGStrutsTestCaseTest.java
+++ b/plugins/testng/src/test/java/org/apache/struts2/testng/TestNGStrutsTestCaseTest.java
@@ -16,11 +16,12 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-package org.apache.struts2;
+package org.apache.struts2.testng;
 
 import junit.framework.TestCase;
 
 import org.apache.struts2.dispatcher.Dispatcher;
+import org.apache.struts2.testng.StrutsTestCase;
 import org.testng.TestListenerAdapter;
 import org.testng.TestNG;
 import org.testng.annotations.Test;
@@ -46,13 +47,13 @@ public class TestNGStrutsTestCaseTest extends TestCase {
             RunTest.mgr = null;
         }
     }
-    
+
     public static class RunTest extends StrutsTestCase {
         public static boolean ran = false;
         public static ConfigurationManager mgr;
         public static Dispatcher du;
-       
-        @Test 
+
+        @Test
         public void testRun() {
             ran = true;
             mgr = this.configurationManager;
diff --git a/core/src/test/java/com/opensymphony/xwork2/TestNGXWorkTestCaseTest.java b/plugins/testng/src/test/java/org/apache/struts2/testng/TestNGXWorkTestCaseTest.java
similarity index 95%
rename from core/src/test/java/com/opensymphony/xwork2/TestNGXWorkTestCaseTest.java
rename to plugins/testng/src/test/java/org/apache/struts2/testng/TestNGXWorkTestCaseTest.java
index 0b543a6a0..dcc7a8c9c 100644
--- a/core/src/test/java/com/opensymphony/xwork2/TestNGXWorkTestCaseTest.java
+++ b/plugins/testng/src/test/java/org/apache/struts2/testng/TestNGXWorkTestCaseTest.java
@@ -16,10 +16,11 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-package com.opensymphony.xwork2;
+package org.apache.struts2.testng;
 
 import com.opensymphony.xwork2.config.ConfigurationManager;
 import junit.framework.TestCase;
+import org.apache.struts2.testng.TestNGXWorkTestCase;
 import org.testng.TestListenerAdapter;
 import org.testng.TestNG;
 import org.testng.annotations.Test;
@@ -42,12 +43,12 @@ public class TestNGXWorkTestCaseTest extends TestCase {
             RunTest.mgr = null;
         }
     }
-    
+
     @Test
     public static class RunTest extends TestNGXWorkTestCase {
         public static boolean ran = false;
         public static ConfigurationManager mgr;
-        
+
         public void testRun() {
             ran = true;
             mgr = this.configurationManager;
diff --git a/pom.xml b/pom.xml
index cdd13feda..1899ed558 100644
--- a/pom.xml
+++ b/pom.xml
@@ -1112,9 +1112,7 @@
             <dependency>
                 <groupId>org.testng</groupId>
                 <artifactId>testng</artifactId>
-                <version>7.1.0</version>
-                <scope>compile</scope>
-                <optional>true</optional>
+                <version>7.4.0</version>
             </dependency>
 
             <dependency>