Bug 236605 [DataBinding] Duplicate entries in bound list after update
tests/org.eclipse.jface.tests.databinding/src/org/eclipse/core/tests/internal/databinding/beans/JavaBeanObservableListTest.java
JavaBeanObservableList observable = new JavaBeanObservableList(Realm
				.getDefault(), bean,
				new PropertyDescriptor("list", Bean.class), Bean.class);
		assertFalse(bean.hasListeners("list"));
		ChangeEventTracker.observe(observable);
		assertTrue(bean.hasListeners("list"));
	}
	public void testConstructor_SkipsRegisterListener() throws Exception {
		Bean bean = new Bean();
		JavaBeanObservableList observable = new JavaBeanObservableList(Realm
				.getDefault(), bean,
				new PropertyDescriptor("list", Bean.class), Bean.class, false);
		assertFalse(bean.hasListeners("list"));
		ChangeEventTracker.observe(observable);
		assertFalse(bean.hasListeners("list"));
	}
	private static void assertEntry(ListDiffEntry entry, boolean addition,
			int position, Object element) {
		assertEquals("addition", addition, entry.isAddition());
		assertEquals("position", position, entry.getPosition());
		assertEquals("element", element, entry.getElement());
	}
	private static void assertPropertyChangeEvent(Bean bean, Runnable runnable) {
		PropertyChangeTracker listener = new PropertyChangeTracker();
		bean.addPropertyChangeListener(listener);
		
		List old = bean.getList();
		assertEquals(0, listener.count);
		
		runnable.run();