add create user tests

Author: lbalmaceda

src/test/java/com/auth0/json/mgmt/users/UserTest.java

@@ -16,6 +16,16 @@ public class UserTest extends JsonTest<User> {
     private static final String json = "{\"connection\":\"auth0\",\"client_id\":\"client123\",\"password\":\"pwd\",\"verify_password\":true,\"username\":\"usr\",\"email\":\"me@auth0.com\",\"email_verified\":true,\"verify_email\":true,\"phone_number\":\"1234567890\",\"phone_verified\":true,\"verify_phone_number\":true,\"picture\":\"https://pic.ture/12\",\"name\":\"John\",\"nickname\":\"Johny\",\"given_name\":\"John\",\"family_name\":\"Walker\",\"app_metadata\":{},\"user_metadata\":{},\"blocked\":true,\"context\":\"extra information\"}";
     private static final String readOnlyJson = "{\"user_id\":\"user|123\",\"last_ip\":\"10.0.0.1\",\"last_login\":\"2016-02-23T19:57:29.532Z\",\"logins_count\":10,\"created_at\":\"2016-02-23T19:57:29.532Z\",\"updated_at\":\"2016-02-23T19:57:29.532Z\",\"identities\":[]}";
 
+    @Test
+    public void shouldHaveEmptyValuesByDefault() throws Exception{
+        User user = new User();
+        assertThat(user.getValues(), is(notNullValue()));
+
+        User user2 = new User("my-connection");
+        assertThat(user2.getConnection(), is("my-connection"));
+        assertThat(user2.getValues(), is(notNullValue()));
+    }
+
     @Test
     public void shouldSerialize() throws Exception {
         User user = new User("auth0");