request.setServletPath("/login");
request.setMethod("POST");
request.setParameter("username", "user");
request.setParameter("password", "password");
HttpSessionCsrfTokenRepository repository = new HttpSessionCsrfTokenRepository();
CsrfToken token = repository.generateToken(request);
repository.saveToken(token, request, response);
request.setParameter(token.getParameterName(),token.getToken());
when(ReflectionUtils.findMethod(HttpServletRequest.class, "changeSessionId")).thenReturn(method);
loadConfig(SessionManagementDefaultSessionFixationServlet31Config.class);