@Override
    public String authenticateRequest(final HttpServletRequest request) {
        final String smUser = request.getHeader(SITE_MINDER_HEADER.getValue());
        if (smUser == null || smUser.trim().isEmpty()) {
            // SiteMinder has not authenticated the user
            return null;
        } else {
            return smUser;
        }
    }
@Test
    public void willNotAuthenticateAMissingUser() {

        doReturn(null).when(request).getHeader("SM_USER");

        final String authenticatedUser = authenticator.authenticateRequest(request);

        assertThat(authenticatedUser, is(nullValue()));
    }