avoid "2nd instance" test failures. The stack trace was:

java.lang.NullPointerException
	at com.gargoylesoftware.htmlunit.html.HtmlPage.loadFrames(HtmlPage.java:1732)
	at com.gargoylesoftware.htmlunit.html.HtmlPage.initialize(HtmlPage.java:153)
	at com.gargoylesoftware.htmlunit.WebClient.loadWebResponseInto(WebClient.java:455)
	at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:340)
	at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:390)
	at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:377)
	at org.jvnet.hudson.test.HudsonTestCase$WebClient.getPage(HudsonTestCase.java:1002)
	at org.jvnet.hudson.test.HudsonTestCase.tearDown(HudsonTestCase.java:257)
	at junit.framework.TestCase.runBare(TestCase.java:130)
	at junit.framework.TestResult$1.protect(TestResult.java:106)
	at junit.framework.TestResult.runProtected(TestResult.java:124)
	at junit.framework.TestResult.run(TestResult.java:109)
	at junit.framework.TestCase.run(TestCase.java:118)
	at junit.framework.TestSuite.runTest(TestSuite.java:208)
	at junit.framework.TestSuite.run(TestSuite.java:203)
	at sun.reflect.GeneratedMethodAccessor232.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.apache.maven.surefire.junit.JUnitTestSet.execute(JUnitTestSet.java:213)
	at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.executeTestSet(AbstractDirectoryTestSuite.java:140)
	at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.execute(AbstractDirectoryTestSuite.java:127)
	at org.apache.maven.surefire.Surefire.run(Surefire.java:177)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.apache.maven.surefire.booter.SurefireBooter.runSuitesInProcess(SurefireBooter.java:345)
	at org.apache.maven.surefire.booter.SurefireBooter.main(SurefireBooter.java:1009)


git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@21328 71c3de6d-444a-0410-be80-ed276b4c234a

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

@@ -249,29 +249,31 @@ public abstract class HudsonTestCase extends TestCase {
     }
 
     protected void tearDown() throws Exception {
-        // cancel pending asynchronous operations, although this doesn't really seem to be working
-        for (WeakReference<WebClient> client : clients) {
-            WebClient c = client.get();
-            if(c==null) continue;
-            // unload the page to cancel asynchronous operations 
-            c.getPage("about:blank");
+        try {
+            // cancel pending asynchronous operations, although this doesn't really seem to be working
+            for (WeakReference<WebClient> client : clients) {
+                WebClient c = client.get();
+                if(c==null) continue;
+                // unload the page to cancel asynchronous operations
+                c.getPage("about:blank");
+            }
+            clients.clear();
+        } finally {
+            server.stop();
+            for (LenientRunnable r : tearDowns)
+                r.run();
+
+            hudson.cleanUp();
+            env.dispose();
+            ExtensionList.clearLegacyInstances();
+            DescriptorExtensionList.clearLegacyInstances();
+
+            // Hudson creates ClassLoaders for plugins that hold on to file descriptors of its jar files,
+            // but because there's no explicit dispose method on ClassLoader, they won't get GC-ed until
+            // at some later point, leading to possible file descriptor overflow. So encourage GC now.
+            // see http://bugs.sun.com/view_bug.do?bug_id=4950148
+            System.gc();
         }
-        clients.clear();
-
-        server.stop();
-        for (LenientRunnable r : tearDowns)
-            r.run();
-
-        hudson.cleanUp();
-        env.dispose();
-        ExtensionList.clearLegacyInstances();
-        DescriptorExtensionList.clearLegacyInstances();
-
-        // Hudson creates ClassLoaders for plugins that hold on to file descriptors of its jar files,
-        // but because there's no explicit dispose method on ClassLoader, they won't get GC-ed until
-        // at some later point, leading to possible file descriptor overflow. So encourage GC now.
-        // see http://bugs.sun.com/view_bug.do?bug_id=4950148
-        System.gc();
     }
 
     protected void runTest() throws Throwable {