使用HttpUnit时，如何向select控件赋值？
假设某JSP中有select控件如下：
<select name= "color ">
<option value= "red "> Red </option>
<option value= "green "> Green </option>
<option value= "blue "> Blue </option>
</select>

我通过form.setParameter( "color ", "green ");赋值，却提示：
com.meterware.httpunit.IllegalParameterValueException: May not set parameter 'color ' to 'blue '. Value must be one of: { }

请同道指点，谢谢！

public void testExecute1() throws Exception
{
WebConversation wc = new WebConversation();
WebRequest request = new GetMethodWebRequest( "http://127.0.0.1:8088/struts-cookbook-1.3.8/ ");
WebResponse response = wc.getResponse(request);
WebLink link = response.getLinkWith( "Execute ");
assertNotNull( "superLink 'Execute ' is null ", link);

WebResponse responseOfExecute = link.click();
WebForm form = responseOfExecute.getFormWithID( "simpleForm ");
assertNotNull( "form 'simpleForm ' is null ", form);

assertTrue( "no parameter named 'color ' ", form.hasParameterNamed( "color "));
form.setParameter( "color ", "green "); // throws exception
}

[解决办法]
给select赋值？？？？？