@Test
 public void testLookupException() {
   HttpRequest request = HttpObjectFactory.createHttpRequest("GET", "");
   HttpContext context = HttpObjectFactory.createHttpContext();
   assertNull(mapper.lookup(request, context));
 }
 @Test
 public void testLookup() {
   HttpRequest request = HttpObjectFactory.createHttpRequest("GET", "/");
   HttpContext context = HttpObjectFactory.createHttpContext();
   assertEquals(VelocityHttpHandler.class, mapper.lookup(request, context).getClass());
 }