}
        };

        SsoAuthenticator authenticator = ssoManager.getAuthenticator();
        assertNull(authenticator);
    }

    // Test register() and getAuthenticators() methods
    @Test
    public void test_register_singleAuthenticator() {
        ssoManager.register(testAuthenticator);
        SsoAuthenticator[] authenticators = ssoManager.getAuthenticators();

        String logoutResult = authenticator.logout(user);
        assertEquals(logoutUrl, logoutResult);
    }

    // Test implementation of SsoAuthenticator for testing
    private static class TestSsoAuthenticator implements SsoAuthenticator {
        private LoginCredential loginCredential;
        private FessLoginAssist.LoginCredentialResolver lastResolver;
        private boolean resolverCalled = false;