The test fails from time to time (about once a month). I have no idea why. 
Something is apperantly broken, maybe in nodes as the test operates just on 
models, no UI, no datasystems, etc.  
 
Probably it is necessary to add more logging to the code and the test to find 
out what is wrong. 
  
  
testRemoveInMiddle: 
      junit.framework.AssertionFailedError: One addition expected:<1> but 
was:<0> 
        at junit.framework.Assert.fail(Assert.java:47) 
        at junit.framework.Assert.failNotEquals(Assert.java:282) 
        at junit.framework.Assert.assertEquals(Assert.java:64) 
        at junit.framework.Assert.assertEquals(Assert.java:201) 
        at 
org.openide.explorer.view.ContextTreeViewModelTest$Listener.assertEvents(ContextTreeViewModelTest.java:210) 
        at 
org.openide.explorer.view.ContextTreeViewModelTest.testRemoveInMiddle(ContextTreeViewModelTest.java:170) 
        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:585) 
        at junit.framework.TestCase.runTest(TestCase.java:154) 
        at org.netbeans.junit.NbTestCase.runBare(NbTestCase.java:135) 
        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 org.netbeans.junit.NbTestCase.access$001(NbTestCase.java:33) 
        at org.netbeans.junit.NbTestCase$1.run(NbTestCase.java:105) 
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:199) 
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:461) 
        at 
java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:242) 
        at 
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163) 
        at 
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157) 
        at 
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149) 
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)