How to set "roles" in the createUser_shouldCreateANewUserWithRoles() @test method.

gistfile1.txt

 /**
     * @see UserController#createUser(SimpleObject,WebRequest)
     * @throws Exception 
     * @verifies create a new user
     */
    @Test
    public void createUser_shouldCreateANewUserWithRoles() throws Exception {

        long originalCount = getAllCount();

        SimpleObject user = new SimpleObject();
        user.add("username", "test user");
        user.add("password", "Secret123");
        user.add("person", "da7f524f-27ce-4bb2-86d6-6d1d05312bd5");
        user.add("roles", new String[] {"3480cb6d-c291-46c8-8d3a-96dc33d199fb"});

        String json = new ObjectMapper().writeValueAsString(user);

        MockHttpServletRequest req = request(RequestMethod.POST, getURI());
        req.setContent(json.getBytes());

        SimpleObject newUser = deserialize(handle(req));

        Util.log("Created User", newUser);
        Assert.assertNotNull(PropertyUtils.getProperty(newUser, "uuid"));
        Assert.assertEquals(originalCount + 1, getAllCount());

    }