@Test
    void testEqualFilter() {
        test("a=1");
        test("(a=1)");

        test("displayName=John Smith");
        test("(displayName=John Smith)");
    }
@author James Chen
        <p>
        TODO: Add tests for invalid filters.
turms-gateway/src/test/java/unit/im/turms/gateway/infra/ldap/FilterTest.java