public void testPut() { CompositeMap map = new CompositeMap(buildOne(), buildTwo(), new CompositeMap.MapMutator() { public void resolveCollision(CompositeMap composite, Map existing, Map added, Collection intersect) { throw new UnsupportedOperationException(); } public Object put(CompositeMap map, Map[] composited, Object key, Object value) { pass = true; return "foo"; } public void putAll(CompositeMap map, Map[] composited, Map t) { throw new UnsupportedOperationException(); } }); map.put("willy", "wonka"); assertTrue(pass); }