source: class TestRegistry {
  
     @Test
     public void register()
     {
  
target:       Registry registry = Registry.instance();
        registry.register(String.class, "Hello");
        Assert.assertEquals(registry.unregister(String.class), "Hello");
  
        Assert.assertFalse(registry.isMapperRegistered(ContentTypeEx.SMILE));
        Assert.assertTrue(registry.isMapperRegistered(ContentType.APPLICATION_JSON));
  
        ObjectMapper mapper = new ObjectMapper();
        registry.registerMapper("any/one", mapper);
        Assert.assertEquals(registry.unregisterMapper("any/one"), mapper);
  
        registry.registerMapper(ContentType.APPLICATION_SVG_XML, mapper);
        Assert.assertEquals(registry.unregisterMapper(ContentType.APPLICATION_SVG_XML), mapper);
  
        Registry.reset();
     }
  
  }