junit spring servlet handlerequest testing

//2013-01-10 johnpfeiffer

package net.kittyandbear;

import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertEquals;

import org.apache.log4j.Logger;
import org.easymock.EasyMock;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Ignore;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ErrorCollector;
import org.springframework.context.support.StaticMessageSource;
import org.springframework.mock.web.MockHttpServletRequest;
import org.springframework.mock.web.MockHttpServletResponse;


public class ServletControllerTest {

    private static final Logger logger = Logger.getLogger( ServletController.class.getName() );

    @Rule
    public ErrorCollector errorCollector = new ErrorCollector();

    private ServletController servletController;

    @Before
    public void setUp() throws Exception {
        servletController = new ServletController();
    }

    @Test
    public void parameter_Null_Redirects_To_Error_Page() throws Exception {
        // Given:
        MockHttpServletRequest request = new MockHttpServletRequest();
        MockHttpServletResponse response = new MockHttpServletResponse();

        final String defaultErrorTitle = "default error title";
        final String defaultErrorMessage = "default error message";
        StaticMessageSource fakeMessageSource = new StaticMessageSource();
        fakeMessageSource.addMessage( "error.title.DEFAULT", request.getLocale(), defaultErrorTitle );
        fakeMessageSource.addMessage( "error.message.DEFAULT", request.getLocale(), defaultErrorMessage );
        servletController.setMessageSource( fakeMessageSource );

        // When:
        servletController.handleRequest( request, response );

        // Then:
        assertEquals( defaultErrorTitle, request.getSession().getAttribute( "errorTitle" ) );
        assertEquals( defaultErrorMessage, request.getSession().getAttribute( "errorMessage" ) );
        assertEquals( ServletController.VIEW_FOLDER + "/" + ServletController.JSP_ERROR, response.getForwardedUrl() );
        EasyMock.verify();
    }

} // end class


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EXAMPLE SERVLET

    protected static final String VIEW_FOLDER = "view";
    protected static final String JSP_ERROR = "error.jsp";

        public void setMessageSource( MessageSource messageSource ) {   //TODO: use builder pattern to ensure this is not null!
        this.messageSource = messageSource;
    }


    @Override
    public void handleRequest( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException {
        logger.debug( "handleRequest()" );
        RequestDispatcher dispatcher = null;

        if( parameter == null ) ) {
            request.getSession().setAttribute( "errorTitle", this.retrieveMessage( request, "error.title.DEFAULT" ) );
            request.getSession().setAttribute( "errorMessage", this.retrieveMessage( request, "error.message.DEFAULT" ) );
            dispatcher = request.getRequestDispatcher( VIEW_FOLDER + "/" + JSP_ERROR );
    }
    dispatcher.forward( request, response );