@Test
public void testAddBubble() {

    // Setup
    final String key = "key";
    final BubbleMessage bubbleMessage = mock(BubbleMessage.class);
    // Run the test
    bubbleCacheUnderTest.addBubble(key, bubbleMessage);
    // Verify the results
    assertEquals(bubbleCacheUnderTest.getBubble(key).get(), bubbleMessage);
}