}

    @ParameterizedTest
    @MethodSource("domains")
    @DisplayName("getUserDomain handles null and empty")
    void getUserDomain_edges(String domain) {
        TestCredentials creds = new TestCredentials(domain, false, false, new Subject(), false);
        assertEquals(domain, creds.getUserDomain());
    }

    static Stream<String> domains() {
        return Stream.of(null, "", "SALES");
    }

* **TCP doesn't know about "domains"**. Only about IP addresses.
    * The information about the **specific domain** requested goes in the **HTTP data**.
* The **HTTPS certificates** "certify" a **certain domain**, but the protocol and encryption happen at the TCP level, **before knowing** which domain is being dealt with.

        // Test User SID (type 1)
        assertEquals("1Test User", sambaHelper.getAccountId(createMockSID(1, "Test User")));

        // Test Domain Group SID (type 2)
        assertEquals("2Domain Group", sambaHelper.getAccountId(createMockSID(2, "Domain Group")));

        // Test Alias SID (type 4, mapped to 2)
        assertEquals("2Local Group", sambaHelper.getAccountId(createMockSID(4, "Local Group")));

        public LsarTrustInformation[] domains;
        /** Maximum count of domains. */
        public int max_count;

        @Override
        public void encode(NdrBuffer _dst) throws NdrException {
            _dst.align(4);
            _dst.enc_ndr_long(count);
            _dst.enc_ndr_referent(domains, 1);
            _dst.enc_ndr_long(max_count);

            if (domains != null) {

gc.ca

// cat : https://www.iana.org/domains/root/db/cat.html
cat

// cc : https://www.iana.org/domains/root/db/cc.html
cc

// cd : https://www.iana.org/domains/root/db/cd.html
// see also: https://www.nic.cd/domain/insertDomain_2.jsp?act=1
cd
gov.cd

// cf : https://www.iana.org/domains/root/db/cf.html
cf

// cg : https://www.iana.org/domains/root/db/cg.html
cg

   * </ul>
   *
   * @param domain A domain name (not IP address)
   * @throws IllegalArgumentException if {@code domain} is not syntactically valid according to
   *     {@link #isValid}
   * @since 10.0 (previously named {@code fromLenient})
   */
  @CanIgnoreReturnValue // TODO(b/219820829): consider removing
  public static InternetDomainName from(String domain) {
    return new InternetDomainName(checkNotNull(domain));

        // Test with null
        serverData.oemDomainName = null;
        assertNull(serverData.oemDomainName);

        // Test with special characters
        serverData.oemDomainName = "DOMAIN-01.LOCAL";
        assertEquals("DOMAIN-01.LOCAL", serverData.oemDomainName);

        // Test with Unicode characters
        serverData.oemDomainName = "ドメイン";
        assertEquals("ドメイン", serverData.oemDomainName);
    }

		[size_is(num_sids)] LsarSidPtr *sids;
	} LsarSidArray;

	typedef enum {
		SID_NAME_USE_NONE = 0, /* NOTUSED */
		SID_NAME_USER     = 1, /* user */
		SID_NAME_DOM_GRP  = 2, /* domain group */
		SID_NAME_DOMAIN   = 3, /* domain: don't know what this is */
		SID_NAME_ALIAS    = 4, /* local group */
		SID_NAME_WKN_GRP  = 5, /* well-known group */
		SID_NAME_DELETED  = 6, /* deleted account: needed for c2 rating */

		[size_is(num_sids)] LsarSidPtr *sids;
	} LsarSidArray;

	typedef enum {
		SID_NAME_USE_NONE = 0, /* NOTUSED */
		SID_NAME_USER     = 1, /* user */
		SID_NAME_DOM_GRP  = 2, /* domain group */
		SID_NAME_DOMAIN   = 3, /* domain: don't know what this is */
		SID_NAME_ALIAS    = 4, /* local group */
		SID_NAME_WKN_GRP  = 5, /* well-known group */
		SID_NAME_DELETED  = 6, /* deleted account: needed for c2 rating */

* **TCP weiß nichts über „<abbr title="Domäne, Bereich, Wirkungsraum">Domains</abbr>“**. Nur über IP-Adressen.
    * Die Informationen über die angeforderte **spezifische Domain** befinden sich in den **HTTP-Daten**.
* Die **HTTPS-Zertifikate** „zertifizieren“ eine **bestimmte Domain**, aber das Protokoll und die Verschlüsselung erfolgen auf TCP-Ebene, **ohne zu wissen**, um welche Domain es sich handelt.