Spring Web Flow: query parameter parameter for JUnit test

Introduction

I have a Java / Tomcat / Spring 2.5 / Spring Webflow 2.0.9 web application. To test some of the pages, I created JUnit tests that set values ​​for form objects and simulate requests coming from the browser. The JUnit class looks something like this:

@TestExecutionListeners({ DependencyInjectionTestExecutionListener.class })
@ContextConfiguration(locations = { "classpath:/WebTests-context.xml", "classpath:/messageSourceConfig.xml" })
@RunWith(SpringJUnit4ClassRunner.class)

public class InitechValidatorTests {

    protected MockHttpSession session;
    protected MockHttpServletRequest request;

    //test methods omitted

    protected void startSession() {
        session = new MockHttpSession();
    }

    protected void endSession() {
        session.clearAttributes();
        session = null;
    }

    protected void startRequest() {
        request = new MockHttpServletRequest();
        request.setSession(session);
        RequestContextHolder.setRequestAttributes(new ServletRequestAttributes(request));

        MockRequestContext mrc = new MockRequestContext();
        org.springframework.webflow.execution.RequestContextHolder.setRequestContext(mrc);

        MessageContext messageContext = org.springframework.webflow.execution.RequestContextHolder.getRequestContext()
                .getMessageContext();
        this.validationContext.setMessageContext(messageContext);
    }

    protected void endRequest() {
        ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).requestCompleted();
        RequestContextHolder.resetRequestAttributes();
        request = null;

        org.springframework.webflow.execution.RequestContextHolder.setRequestContext(null);
    }
}

For each test method, I call the startRequest and endRequest methods (startSession is called before the first test method and endSession after the last test method). Without this design, I could not use, for example. RequestContextHolder in the code I'm testing.

Problem

In the class for validation, I read the contents of the request parameter from the web stream as follows:

RequestContext requestContext = RequestContextHolder.getRequestContext();
ExternalContext externalContext = requestContext.getExternalContext();
String printPressed = externalContext.getRequestParameterMap().get("printPressed");

"printPressed" JUnit :

org.springframework.webflow.execution.RequestContext requestContext = org.springframework.webflow.execution.RequestContextHolder
                    .getRequestContext();
ExternalContext externalContext = requestContext.getExternalContext();
Map requestParamMap = externalContext.getRequestParameterMap().asMap();
requestParamMap.put("printPressed", "true");

, , , UnsupportedOperationException.

: requestParameterMap org.springframework.webflow.context.ExternalContext? , getRequestParameterMap, , . , , , MockParameterMap, : " , . ".

MockParameterMap ExternalContext ? ?