cactus test session attributes

I have created cactus tests and want to test servlet doGet() method. I have the next code:

if (action.startsWith("/projects")) {
            try {
                int categoryid = Integer.valueOf(req.getParameter("category"));

                List<Project> projects_with_category = projects.getContainer(categories.getById(categoryid));

                session.setAttribute("projects", projects_with_category);
                req.getRequestDispatcher("views/projects.jsp").forward(req, resp);
            } catch (NumberFormatException | IndexOutOfBoundsException e) {
                session.setAttribute("error", "error");
                resp.sendRedirect("/categories");
            }
        } else if (action.startsWith("/project")) {
            List<Project> projects = (List<Project>) session.getAttribute("projects");
            System.out.println(projects);
            try {
                int projectid = Integer.valueOf(req.getParameter("projectid"));

                for( Project project: projects) {
                    if(project.getId() == projectid) {
                        session.setAttribute("project", project);

                        req.getRequestDispatcher("views/project.jsp").forward(req, resp);
                        return;
                    }
                }

The cactus tests:

public void begin2ProjectsTest(WebRequest request) {
        request.setURL(null, null, "/projects", null, null);
        request.addParameter("category", "1");
    }
    public void test2ProjectsTest() throws ServletException, IOException {
        mainservlet.doGet(request, response);
        assertNotNull(this.session.getAttribute("categoryid"));
        assertNotNull(this.session.getAttribute("projects"));
        projs = new ArrayList<Project>((List<Project>)this.session.getAttribute("projects"));
    }

public void begin4ProjectTest(WebRequest request) {
        request.setURL(null, null, "/project", null, null);
        request.addParameter("projectid", "1");
        session.setAttribute("projects", projs);
    }
    public void test4ProjectTest() throws ServletException, IOException {
        mainservlet.doGet(request, response);
        assertNotNull(this.session.getAttribute("project"));
    }

The problem is that attribute "projects" available in first test become null in second what ever I did((( I even created List to copy "projects" but it still null in second project((( I can not test it(((