Test problem with EntityController, waiting online for answe

[seto]

The register component injected a DAO. When the DAO extends EntityController, when only one test exists, it runs normal;when two tests or above the second test will throw exception that entityManager is closed.When the DAO injects the EntityManager directly, doesn't extend the EntityController which encapsulate a EntityManager, no matter how many tests exist, it runs normal. Why?

package com.kdccn.test;

import static org.testng.Assert.*;

import java.util.*;

import org.testng.annotations.*;

import org.jboss.seam.mock.*;

import com.kdccn.util.*;

public class UserTest extends SeamTest {

 @Test
 public void testLogin() throws Exception {
 new FacesRequest("/user/login.xhtml") {
 @Override
 protected void updateModelValues() {
 setValue("#{identity.username}", "admin");
 setValue("#{identity.password}", "secret");
 }

 @Override
 protected void invokeApplication() {
 invokeAction("#{identity.login}");
 }
 }.run();
 }

 @Test
 public void testRegister() throws Exception {
 new FacesRequest("/user/register.xhtml") {
 @Override
 protected void updateModelValues() {
 setValue("#{newUser.email}", "[e-mail]");
 setValue("#{newUser.qq}", 61304189L);
 setValue("#{newUser.icq}", 259833852L);
 setValue("#{newUser.kugoo}", 318921L);
 setValue("#{newUser.msn}", "[e-mail]");
 setValue("#{newUser.yahoo}", "[e-mail]");
 setValue("#{newUser.google}", "[e-mail]");
 setValue("#{newUser.alipay}", "[e-mail]");
 setValue("#{newUser.wangwang}", "setokaiba");
 setValue("#{newUser.website}", "www.kdccn.com");
 setValue("#{newUser.question}", "secret");
 setValue("#{newUser.answer}", "secret");
 setValue("#{newUser.place}", "China");
 setValue("#{newUser.phone}", "[phone]");
 Calendar calendar = Calendar.getInstance();
 calendar.set(1987, Calendar.DECEMBER, 30);
 setValue("#{newUser.birthday}", calendar.getTime());
 setValue("#{newUser.description}", "Nothing");
 setValue("#{newUser.firstname}", "Seto");
 setValue("#{newUser.lastname}", "Kaiba");
 setValue("#{newUser.nickname}", "Seto");
 setValue("#{newUser.username}", "SetoKaiba");
 setValue("#{register.password}", "secret");
 setValue("#{register.confirm}", "secret");
 setValue("#{register.gender}", "Male");
 }

 @Override
 protected void invokeApplication() {
 invokeAction("#{register.register}");
 }

 @Override
 protected void renderResponse() {
 assertNotNull(getValue("#{newUser.id}"));
 assertEquals(getValue("#{newUser.hashedPassword}"), Hash
 .instance().hash("secret"));
 assertTrue((Boolean) getValue("#{s:hasRole('user')}"));
 }
 }.run();
 }
}