@Test
    void verifyOperation() {
        assertNotNull(NullPrincipal.getInstance().getId());
    }
This is {@link NullPrincipalTests}.

@author Misagh Moayyed
@since 6.3.0
core/cas-server-core-authentication-api/src/test/java/org/apereo/cas/authentication/principal/resolvers/NullPrincipalTests.java