@Test
public void testGetAttributesSortedStringSetNotExists() throws Exception {

	final Attributes attrs = new BasicAttributes();
	class TestableDirContextAdapter extends DirContextAdapter {
		public TestableDirContextAdapter() {
			super(attrs, null);
		}
	}
	tested = new TestableDirContextAdapter();
	SortedSet s = tested.getAttributeSortedStringSet("abc");
	assertThat(s).isNull();
}