BubbleCache { public void addBubble(String key,BubbleMessage bubbleMessage) { this.cache.put(key, bubbleMessage); }  void addBubble(String key,BubbleMessage bubbleMessage); Optional<BubbleMessage> getBubble(String eventId);  }
@Test public void testAddBubble() { final String key = "key"; final BubbleMessage bubbleMessage = mock(BubbleMessage.class); bubbleCacheUnderTest.addBubble(key, bubbleMessage); assertEquals(bubbleCacheUnderTest.getBubble(key).get(), bubbleMessage); }