@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 willAuthenticateAUserWithDifferentHeader() {

        final String userId = "a-test-user";
        final String header = "a-custom-header";
        SiteMinderServletRequestAuthenticator.SITE_MINDER_HEADER.setValue(header);
        doReturn(userId).when(request).getHeader(header);

        final String authenticatedUser = authenticator.authenticateRequest(request);

        assertThat(authenticatedUser, is(userId));
    }