如何使用Spring对portlet进行单元测试？

Question

我试图使用Spring对一个简单的portlet进行单元测试。以下是我到目前为止所做的......

import static org.hamcrest.core.IsEqual.equalTo;
import static org.junit.Assert.assertThat;

import java.io.IOException;

import javax.portlet.GenericPortlet;
import javax.portlet.PortletException;

import org.junit.Test;
import org.springframework.mock.web.portlet.MockPortletConfig;
import org.springframework.mock.web.portlet.MockRenderRequest;
import org.springframework.mock.web.portlet.MockRenderResponse;

public class HelloWorldPortletTest {

   @Test
   public void testDoView() throws PortletException, IOException {              
      MockRenderResponse renderResponse = new MockRenderResponse();

      GenericPortlet portlet = new HelloWorldPortlet();     
      portlet.init(new MockPortletConfig());
      portlet.render(new MockRenderRequest(), renderResponse);

      assertThat(renderResponse.getContentType(), equalTo("text/html"));
      assertThat(renderResponse.getContentAsString(), equalTo("Hello Portlet" + System.getProperty("line.separator")));
   }
}

不幸的是，当我运行它时，我得到以下NullPointerException：

java.lang.NullPointerException
at javax.portlet,GenericPortlet.getTitle(GenericPortlet.java:281)
at stuff.HelloWorldPortlet.getTitle(HelloWorldPortlet.java:126)
at javax.portlet.GenericPortlet.render(GenericPortlet.java:252)
at stuff.HelloWorldPortlet.render(HelloWorldPortlet.java:94)
at stuff.HelloWorldPortletTest.testDoView(HelloWorldPortletTest.java:24)

如何让Spring读入portlet.xml文件，以便GenericPortlet的getTitle（）方法不返回null？