WW-5382 Rework existing Dispatcher tests and base test classes

core/src/main/java/com/opensymphony/xwork2/XWorkJUnit4TestCase.java

@@ -51,10 +51,6 @@ public void setUp() throws Exception {
     @After
     public void tearDown() throws Exception {
         XWorkTestCaseHelper.tearDown(configurationManager);
-        configurationManager = null;
-        configuration = null;
-        container = null;
-        actionProxyFactory = null;
     }
 
     protected void loadConfigurationProviders(ConfigurationProvider... providers) {

core/src/main/java/com/opensymphony/xwork2/XWorkTestCase.java

@@ -64,10 +64,6 @@ protected void setUp() throws Exception {
     @Override
     protected void tearDown() throws Exception {
         XWorkTestCaseHelper.tearDown(configurationManager);
-        configurationManager = null;
-        configuration = null;
-        container = null;
-        actionProxyFactory = null;
     }
 
     protected void loadConfigurationProviders(ConfigurationProvider... providers) {

core/src/main/java/org/apache/struts2/dispatcher/ContainerHolder.java

@@ -23,25 +23,25 @@
 /**
  * Simple class to hold Container instance per thread to minimise number of attempts
  * to read configuration and build each time a new configuration.
- *
+ * <p>
  * As ContainerHolder operates just per thread (which means per request) there is no need
  * to check if configuration changed during the same request. If changed between requests,
  * first call to store Container in ContainerHolder will be with the new configuration.
  */
 class ContainerHolder {
 
-    private static ThreadLocal<Container> instance = new ThreadLocal<>();
+    private static final ThreadLocal<Container> instance = new ThreadLocal<>();
 
-    public static void store(Container instance) {
-        ContainerHolder.instance.set(instance);
+    public static void store(Container newInstance) {
+        instance.set(newInstance);
     }
 
     public static Container get() {
-        return ContainerHolder.instance.get();
+        return instance.get();
     }
 
     public static void clear() {
-        ContainerHolder.instance.remove();
+        instance.remove();
     }
 
 }

core/src/main/java/org/apache/struts2/dispatcher/Dispatcher.java

@@ -367,7 +367,7 @@ public void cleanup() {
         }
 
         // clean up Dispatcher itself for this thread
-        instance.set(null);
+        instance.remove();
         servletContext.setAttribute(StrutsStatics.SERVLET_DISPATCHER, null);
 
         // clean up DispatcherListeners

core/src/main/java/org/apache/struts2/util/StrutsTestCaseHelper.java

@@ -28,19 +28,17 @@
 import javax.servlet.ServletContext;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
-import java.util.HashMap;
 import java.util.Map;
 
+import static java.util.Collections.emptyMap;
+
 /**
- * Generic test setup methods to be used with any unit testing framework. 
+ * Generic test setup methods to be used with any unit testing framework.
  */
 public class StrutsTestCaseHelper {
-
-    public static Dispatcher initDispatcher(ServletContext ctx, Map<String,String> params) {
-        if (params == null) {
-            params = new HashMap<>();
-        }
-        Dispatcher du = new DispatcherWrapper(ctx, params);
+
+    public static Dispatcher initDispatcher(ServletContext ctx, Map<String, String> params) {
+        Dispatcher du = new DispatcherWrapper(ctx, params != null ? params : emptyMap());
         du.init();
         Dispatcher.setInstance(du);
 
@@ -52,7 +50,15 @@ public static Dispatcher initDispatcher(ServletContext ctx, Map<String,String> p
         return du;
     }
 
-    public static void tearDown() throws Exception {
+    public static void tearDown(Dispatcher dispatcher) {
+        if (dispatcher != null && dispatcher.getConfigurationManager() != null) {
+            dispatcher.cleanup();
+        }
+        tearDown();
+    }
+
+    public static void tearDown() {
+        (new Dispatcher(null, null)).cleanUpAfterInit(); // Clear ContainerHolder
         Dispatcher.setInstance(null);
         ActionContext.clear();
     }

core/src/test/java/org/apache/struts2/StrutsInternalTestCase.java

@@ -75,12 +75,7 @@ protected Dispatcher initDispatcherWithConfigs(String configs) {
 
     @Override
     protected void tearDown() throws Exception {
-        // maybe someone else already destroyed Dispatcher
-        if (dispatcher != null && dispatcher.getConfigurationManager() != null) {
-            dispatcher.cleanup();
-            dispatcher = null;
-        }
-        StrutsTestCaseHelper.tearDown();
+        StrutsTestCaseHelper.tearDown(dispatcher);
     }
 
     /**

core/src/test/java/org/apache/struts2/StrutsJUnit4InternalTestCase.java

@@ -0,0 +1,61 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.struts2;
+
+import com.opensymphony.xwork2.ActionProxyFactory;
+import com.opensymphony.xwork2.XWorkJUnit4TestCase;
+import org.apache.struts2.dispatcher.Dispatcher;
+import org.apache.struts2.util.StrutsTestCaseHelper;
+import org.apache.struts2.views.jsp.StrutsMockServletContext;
+import org.junit.After;
+import org.junit.Before;
+
+import java.util.Map;
+
+public class StrutsJUnit4InternalTestCase extends XWorkJUnit4TestCase {
+
+    protected StrutsMockServletContext servletContext;
+    protected Dispatcher dispatcher;
+
+    @Override
+    @Before
+    public void setUp() throws Exception {
+        initDispatcher();
+    }
+
+    @Override
+    @After
+    public void tearDown() throws Exception {
+        StrutsTestCaseHelper.tearDown(dispatcher);
+    }
+
+    protected void initDispatcher() {
+        initDispatcher(null);
+    }
+
+    protected void initDispatcher(Map<String, String> params) {
+        StrutsTestCaseHelper.tearDown();
+        servletContext = new StrutsMockServletContext();
+        dispatcher = StrutsTestCaseHelper.initDispatcher(servletContext, params);
+        configurationManager = dispatcher.getConfigurationManager();
+        configuration = configurationManager.getConfiguration();
+        container = configuration.getContainer();
+        actionProxyFactory = container.getInstance(ActionProxyFactory.class);
+    }
+}