Bug 296253 [CommonNavigator] An empty label is not properly shown when it is the only contributed label
tests/org.eclipse.ui.tests.navigator/src/org/eclipse/ui/tests/navigator/LabelProviderTest.java
TreeItem[] rootItems = _viewer.getTree().getItems();
		
		if (!rootItems[0].getText().startsWith("Red"))
			fail("Wrong text: " + rootItems[0].getText());
	}
	public void testBlankLabelProviderOverride() throws Exception {
		blankLabelProviderOverride(BLANK, "");
	}	
	
	public void testNullLabelProviderOverride() throws Exception {
		blankLabelProviderOverride(NULL, "");
	}	
	
	public void testPlainBlankLabelProviderOverride() throws Exception {
		blankLabelProviderOverride(BLANK, PLAIN);
	}	
	
	public void testPlainNullLabelProviderOverride() throws Exception {
		blankLabelProviderOverride(NULL, PLAIN);
	}	
	
	private void checkItemsAll(TreeItem[] rootItems, TestLabelProvider tlp) {
		if (!rootItems[0].getText().startsWith(tlp.getColorName()))
			fail("Wrong text: " + rootItems[0].getText());
		checkItems(rootItems, tlp);
	}
	
	private void checkItems(TreeItem[] rootItems, TestLabelProvider tlp) {
		assertEquals(tlp.backgroundColor, rootItems[0]
				.getBackground(0));