Bug 263207 [CommonNavigator] Improve DnD tracing and add DnD test suite
There are no DnD tests for the Common Navigator. Also, the CNF has many test utility classes (basically stolen from JDT), these should be moved into a lower level area, and it looks like org.eclipse.ui.test.harness is a good place. (Perhaps we can get the JDT to use these identical versions as well so there is only one copy that everyone uses). Finally, the DnD tracing needs to be improved to show more information and show it more concisely.
tests/org.eclipse.ui.tests.navigator/src/org/eclipse/ui/tests/navigator/INavigatorContentServiceTests.java
contentServiceWithProgrammaticBindings
				.getActivationService()
				.activateExtensions(
						new String[] { RESOURCE_EXTENSION_ID,
								TEST_EXTENSION_ID, TEST_EXTENSION_2_ID }, false);
		assertEquals("One descriptor should have been returned.", 1,
				boundDescriptors.length);
		assertEquals(
				"The declarative content service should have one fewer visible extension ids than the one created programmatically.",
				contentService.getVisibleExtensionIds().length + 1,
				contentServiceWithProgrammaticBindings.getVisibleExtensionIds().length);
		INavigatorContentDescriptor[] visibleDescriptors = contentServiceWithProgrammaticBindings
				.getVisibleExtensions();
		boolean found = false;
		for (int i = 0; i < visibleDescriptors.length; i++)
			if (TEST_EXTENSION_2_ID.equals(visibleDescriptors[i].getId()))
				found = true;
		assertTrue("The programmatically bound extension should be bound.",
				found);
		Set enabledDescriptors = contentServiceWithProgrammaticBindings
				.findContentExtensionsByTriggerPoint(project);
		assertEquals("There should be a three extensions.", 3,
				enabledDescriptors.size());
	}
	public void testTestExtensionVisibility() {
		assertTrue("The test extension should be visible.", contentService
				.getViewerDescriptor().isVisibleContentExtension(
						TEST_EXTENSION_ID));
	}
	public void testResourceExtensionVisibility() {