Tsk Tsk! Kohsuke you missed a possible NPE for people running hpi:run on...

Tsk Tsk! Kohsuke you missed a possible NPE for people running hpi:run on plugins in fixing [JENKINS-6545]

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

@@ -93,6 +93,8 @@ public class TestExtensionLoader extends ExtensionFinder {
     }
 
     private boolean isActive(TestEnvironment env, Class<?> extType) {
+        if (env == null || env.testCase == null)
+            return false;
         for (Class<?> outer = extType; outer!=null; outer=outer.getEnclosingClass())
             if (outer.isInstance(env.testCase))
                 return true;      // enclosed