ctx.put(PortletActionConstants.MODE_NAMESPACE_MAP, modeMap);
ValueStack stack = ctx.getValueStack();
URL url = new URL(stack, new PortletServletRequest(request, null),
new PortletServletResponse(response));
MockActionInvocation ai = new MockActionInvocation();
MockActionProxy ap = new MockActionProxy();
ap.setActionName("testAction");
ap.setNamespace("/current_namespace");
ai.setProxy(ap);
ai.setStack(stack);
ai.setAction(new Object());
ctx.setActionInvocation(ai);
StringWriter renderOutput = new StringWriter();
renderer.renderUrl(renderOutput, url);