@Test
    void verifyNonNullPrincipal() throws Throwable {
        val credentials = new PrincipalBearingCredential(PrincipalFactoryUtils.newPrincipalFactory().createPrincipal("scott"));
        assertNotNull(this.handler.authenticate(credentials, mock(Service.class)));
    }
When the credentials bear a Principal, succeed the authentication.
support/cas-server-support-trusted/src/test/java/org/apereo/cas/adaptors/trusted/authentication/handler/support/PrincipalBearingCredentialsAuthenticationHandlerTests.java