@Test
    void testNullToModify() {
        assertThrows(NullPointerException.class, () -> getAttributeMerger().mergeAttributes(null, new HashMap<>()));
    }
This is {@link AbstractAttributeMergerTests}.

@author Misagh Moayyed
@since 7.1.0
core/cas-server-core-authentication-api/src/test/java/org/apereo/cas/authentication/principal/merger/AbstractAttributeMergerTests.java