@Test
public void removeObserver() throws Throwable {

  MockAbstractThreadedPlugin plugin = new MockAbstractThreadedPlugin("addObserverTest");
  ObservablePlugin.PluginObserver obs = getOneObserver();
  // add observer
  plugin.addObserver(obs);
  plugin.removeObserver(obs);
  Assert.assertEquals(0, plugin.countObservers());
  // test if thread is deactivated
  Assert.assertFalse(plugin.isMonitoring());
  // shutdown thread
  plugin.finalize();
}