@Test
public void testRemoveAll() {

	Mappings<Task, Resource> mappings = new Mappings<Task, Resource>();
	Mapping<Task, Resource> mapping = new Mapping<Task, Resource>("m", new Task("t"), new Resource("r"));
	mappings.add(mapping);
	Assert.assertTrue(mappings.removeAll(Collections.singleton(mapping)));
	Assert.assertEquals(0, mappings.size());
	Assert.assertFalse(mappings.removeAll(Collections.singleton(mapping)));
}