@Test
    void testGetPossibleUserAttributeNames() {
        val expectedAttributeNames = new HashSet<String>();
        expectedAttributeNames.add("shirtColor");
        expectedAttributeNames.add("phone");
        var possibleAttributeNames = this.testInstance.getPossibleUserAttributeNames(PersonAttributeDaoFilter.alwaysChoose());
        assertEquals(expectedAttributeNames, possibleAttributeNames);

        var nullBacking = new StubPersonAttributeDao();
        assertEquals(Collections.emptySet(), nullBacking.getPossibleUserAttributeNames(PersonAttributeDaoFilter.alwaysChoose()));
    }
Testcase for {@link StubPersonAttributeDao}.

@author Misagh Moayyed
@since 7.1.0
core/cas-server-core-authentication-api/src/test/java/org/apereo/cas/authentication/attribute/StubPersonAttributeDaoTests.java