[FIXED JENKINS-18259]

Added a listener that gets called at the end of the test to provide opportunity for a cleanup.
This avoids the code duplication between HudsonTestCase vs JenkinsRule, too.

test/src/main/java/org/jvnet/hudson/test/ChannelShutdownListener.java

+package org.jvnet.hudson.test;
+
+import hudson.Extension;
+import hudson.model.Computer;
+import hudson.model.TaskListener;
+import hudson.remoting.Channel;
+import hudson.remoting.VirtualChannel;
+import hudson.slaves.ComputerListener;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Runs at the end of the test to cleanup any live channels.
+ *
+* @author Kohsuke Kawaguchi
+*/
+@Extension
+public class ChannelShutdownListener extends ComputerListener implements EndOfTestListener {
+    /**
+     * Remember channels that are created, to release them at the end.
+     */
+    private List<Channel> channels = new ArrayList<Channel>();
+
+    @Override
+    public synchronized void onOnline(Computer c, TaskListener listener) throws IOException, InterruptedException {
+        VirtualChannel ch = c.getChannel();
+        if (ch instanceof Channel) {
+            channels.add((Channel)ch);
+        }
+    }
+
+    @Override
+    public synchronized void onTearDown() throws Exception {
+        for (Channel c : channels)
+            c.close();
+        for (Channel c : channels)
+            c.join();
+        channels.clear();
+    }
+}

test/src/main/java/org/jvnet/hudson/test/EndOfTestListener.java

+package org.jvnet.hudson.test;
+
+import hudson.ExtensionPoint;
+
+/**
+ * Gets notified before the test completes to perform additional cleanup.
+ *
+ * @author Kohsuke Kawaguchi
+ * @since 1.520
+ */
+public interface EndOfTestListener extends ExtensionPoint {
+    /**
+     * Called for clean up.
+     */
+    void onTearDown() throws Exception;
+}

test/src/main/java/org/jvnet/hudson/test/HudsonTestCase.java

@@ -57,8 +57,6 @@ import hudson.model.*;
 import hudson.model.Executor;
 import hudson.model.Node.Mode;
 import hudson.model.Queue.Executable;
-import hudson.remoting.Channel;
-import hudson.remoting.VirtualChannel;
 import hudson.remoting.Which;
 import hudson.security.ACL;
 import hudson.security.AbstractPasswordBasedSecurityRealm;
@@ -77,7 +75,6 @@ import hudson.tasks.BuildWrapper;
 import hudson.tasks.BuildWrapperDescriptor;
 import hudson.tasks.Builder;
 import hudson.tasks.Mailer;
-import hudson.tasks.Mailer.DescriptorImpl;
 import hudson.tasks.Maven;
 import hudson.tasks.Maven.MavenInstallation;
 import hudson.tasks.Publisher;
@@ -177,7 +174,6 @@ import com.gargoylesoftware.htmlunit.DefaultCssErrorHandler;
 import com.gargoylesoftware.htmlunit.FailingHttpStatusCodeException;
 import com.gargoylesoftware.htmlunit.Page;
 import com.gargoylesoftware.htmlunit.WebRequestSettings;
-import com.gargoylesoftware.htmlunit.WebResponse;
 import com.gargoylesoftware.htmlunit.html.DomNode;
 import com.gargoylesoftware.htmlunit.html.HtmlButton;
 import com.gargoylesoftware.htmlunit.html.HtmlElement;
@@ -234,11 +230,6 @@ public abstract class HudsonTestCase extends TestCase implements RootAction {
      */
     private List<WebClient> clients = new ArrayList<WebClient>();
 
-    /**
-     * Remember channels that are created, to release them at the end.
-     */
-    private List<Channel> channels = new ArrayList<Channel>();
-
     /**
      * JavaScript "debugger" that provides you information about the JavaScript call stack
      * and the current values of the local variables in those stack frame.
@@ -390,6 +381,9 @@ public abstract class HudsonTestCase extends TestCase implements RootAction {
     @Override
     protected void tearDown() throws Exception {
         try {
+            for (EndOfTestListener tl : jenkins.getExtensionList(EndOfTestListener.class))
+                tl.onTearDown();
+
             if (timeoutTimer!=null) {
                 timeoutTimer.cancel();
                 timeoutTimer = null;
@@ -402,15 +396,6 @@ public abstract class HudsonTestCase extends TestCase implements RootAction {
                 client.closeAllWindows();
             }
             clients.clear();
-
-            synchronized(channels) {
-                for (Channel c : channels)
-                    c.close();
-                for (Channel c : channels)
-                    c.join();
-                channels.clear();
-            }
-
         } finally {
             if (server!=null)
                 server.stop();
@@ -545,22 +530,6 @@ public abstract class HudsonTestCase extends TestCase implements RootAction {
         return realm;
     }
 
-    @TestExtension
-    public static class ComputerListenerImpl extends ComputerListener {
-        @Override
-        public void onOnline(Computer c, TaskListener listener) throws IOException, InterruptedException {
-            VirtualChannel ch = c.getChannel();
-            if (ch instanceof Channel)
-            TestEnvironment.get().testCase.addChannel((Channel)ch);
-        }
-    }
-
-    private void addChannel(Channel ch) {
-        synchronized (channels) {
-            channels.add(ch);
-        }
-    }
-    
     /**
      * Returns the older default Maven, while still allowing specification of other bundled Mavens.
      */

test/src/main/java/org/jvnet/hudson/test/JenkinsRule.java

@@ -88,13 +88,10 @@ import hudson.model.TaskListener;
 import hudson.model.UpdateSite;
 import hudson.model.User;
 import hudson.model.View;
-import hudson.remoting.Channel;
-import hudson.remoting.VirtualChannel;
 import hudson.remoting.Which;
 import hudson.security.ACL;
 import hudson.security.AbstractPasswordBasedSecurityRealm;
 import hudson.security.GroupDetails;
-import hudson.security.SecurityRealm;
 import hudson.security.csrf.CrumbIssuer;
 import hudson.slaves.CommandLauncher;
 import hudson.slaves.ComputerConnector;
@@ -135,6 +132,7 @@ import org.junit.rules.TestRule;
 import org.junit.runner.Description;
 import org.junit.runners.model.FrameworkMethod;
 import org.junit.runners.model.Statement;
+import org.jvnet.hudson.test.recipes.Recipe;
 import org.jvnet.hudson.test.rhino.JavaScriptDebugger;
 import org.kohsuke.stapler.ClassDescriptor;
 import org.kohsuke.stapler.DataBoundConstructor;
@@ -173,6 +171,7 @@ import java.lang.management.ThreadInfo;
 import java.lang.reflect.Array;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
+import java.net.HttpURLConnection;
 import java.net.MalformedURLException;
 import java.net.URISyntaxException;
 import java.net.URL;
@@ -229,8 +228,6 @@ public class JenkinsRule implements TestRule, MethodRule, RootAction {
 
     private Description testDescription;
 
-    private static JenkinsRule CURRENT = null;
-
     /**
      * Points to the same object as {@link #jenkins} does.
      */
@@ -264,11 +261,6 @@ public class JenkinsRule implements TestRule, MethodRule, RootAction {
      */
     private List<WebClient> clients = new ArrayList<WebClient>();
 
-    /**
-     * Remember channels that are created, to release them at the end.
-     */
-    private List<Channel> channels = new ArrayList<Channel>();
-
     /**
      * JavaScript "debugger" that provides you information about the JavaScript call stack
      * and the current values of the local variables in those stack frame.
@@ -392,8 +384,11 @@ public class JenkinsRule implements TestRule, MethodRule, RootAction {
     /**
      * Override to tear down your specific external resource.
      */
-    protected void after() {
+    protected void after() throws Exception {
         try {
+            for (EndOfTestListener tl : jenkins.getExtensionList(EndOfTestListener.class))
+                tl.onTearDown();
+
             if (timeoutTimer!=null) {
                 timeoutTimer.cancel();
                 timeoutTimer = null;
@@ -411,20 +406,6 @@ public class JenkinsRule implements TestRule, MethodRule, RootAction {
             }
             clients.clear();
 
-            for (Channel c : channels)
-                try {
-                    c.close();
-                } catch (IOException e) {
-                    // ignore
-                }
-            for (Channel c : channels)
-                try {
-                    c.join();
-                } catch (InterruptedException e) {
-                    // ignore
-                }
-            channels.clear();
-
         } finally {
             try {
                 server.stop();
@@ -476,7 +457,6 @@ public class JenkinsRule implements TestRule, MethodRule, RootAction {
                 Thread t = Thread.currentThread();
                 String o = t.getName();
                 t.setName("Executing "+ testDescription.getDisplayName());
-                CURRENT = JenkinsRule.this;
                 before();
                 try {
                     System.out.println("=== Starting " + testDescription.getDisplayName());
@@ -503,7 +483,6 @@ public class JenkinsRule implements TestRule, MethodRule, RootAction {
                     after();
                     testDescription = null;
                     t.setName(o);
-                    CURRENT = null;
                 }
             }
         };
@@ -615,16 +594,6 @@ public class JenkinsRule implements TestRule, MethodRule, RootAction {
         return realm;
     }
 
-    @TestExtension
-    public static class ComputerListenerImpl extends ComputerListener {
-        @Override
-        public void onOnline(Computer c, TaskListener listener) throws IOException, InterruptedException {
-            VirtualChannel ch = c.getChannel();
-            if (ch instanceof Channel)
-                CURRENT.channels.add((Channel)ch);
-        }
-    }
-
 
     /**
      * Returns the older default Maven, while still allowing specification of other bundled Mavens.