toDelete.add(new Node());
toDelete.add("test");
assertFalse(elements.removeAll(toDelete));
assertSame(parent, child.getParent());
toDelete.add(child);
assertTrue(elements.removeAll(toDelete));
// Check if node was correctly detached from elements
assertEquals(0, elements.size());
assertNull(child.getParent());
assertNull(child.getDocument());