//getProxy().doFilter(request, response, chain);
GeoServerLogoutFilter logoutFilter=
(GeoServerLogoutFilter) getSecurityManager().loadFilter(GeoServerSecurityFilterChain.FORM_LOGOUT_FILTER);
logoutFilter.doFilter(request, response, chain);
assertEquals(HttpServletResponse.SC_OK, response.getErrorCode());
assertTrue(response.wasRedirectSent());
String redirectUrl = response.getHeader("Location");
assertNotNull(redirectUrl);
assertTrue(redirectUrl.contains(GeoServerCasConstants.LOGOUT_URI));
session = (MockHttpSession) request.getSession(false);