// Setup default mock behaviors
        when(ctx.getConfig()).thenReturn(config);
        when(ctx.getNameServiceClient()).thenReturn(nameSvc);
        when(ctx.getCredentials()).thenReturn(creds);
        when(ctx.getTransportPool()).thenReturn(pool);

        // Default config values
        when(config.getLocalAddr()).thenReturn(null);
        when(config.getLocalPort()).thenReturn(0);
        when(config.getSessionLimit()).thenReturn(10);

    }

    @Test
    void testGetDc_Success() throws CIFSException, IOException {
        when(mockConfig.isDfsDisabled()).thenReturn(false);
        when(mockContext.getTransportPool()).thenReturn(mockTransportPool);
        when(mockTransportPool.getSmbTransport(any(), anyString(), anyInt(), anyBoolean(), anyBoolean())).thenReturn(mockTransport);

            // https://lists.samba.org/archive/samba-technical/2009-August/066486.html
            // UniAddress addr = UniAddress.getByName(authDomain, true, tf);
            // SmbTransport trans = tf.getTransportPool().getSmbTransport(tf, addr, 0);
            try (SmbTransport dc = getDc(tf, authDomain)) {
                final CacheEntry<Map<String, CacheEntry<DfsReferralDataInternal>>> entry =

        // Set up mock behaviors
        when(mockContext.getConfig()).thenReturn(mockConfig);
        when(mockContext.getCredentials()).thenReturn(mockCredentials);
        when(mockContext.getTransportPool()).thenReturn(mockTransportPool);
        when(mockConfig.getDfsTtl()).thenReturn(300L);

        // Mock transport to throw IOException - simulating connection failure

        return getChallenge(tf, dc, 0);
    }

    @Override
    public byte[] getChallenge(final CIFSContext tf, final Address dc, final int port) throws SmbException {
        try (SmbTransportInternal trans = tf.getTransportPool()
                .getSmbTransport(tf, dc, port, false, !tf.getCredentials().isAnonymous() && tf.getConfig().isIpcSigningEnforced())
                .unwrap(SmbTransportInternal.class)) {
            trans.ensureConnected();

                    if (log.isDebugEnabled()) {
                        log.debug("Using exclusive transport for " + this);
                    }
                    this.exclusiveTransport = this.ctx.getTransportPool()
                            .getSmbTransport(this.ctx, host, loc.getPort(), true, loc.shouldForceSigning())
                            .unwrap(SmbTransportInternal.class);

            transportContextField.set(ntlmServlet, cifsContext);
        } catch (Exception e) {
            throw new RuntimeException("Failed to inject mock CIFSContext", e);
        }

        when(cifsContext.getTransportPool()).thenReturn(transportPool);
        when(cifsContext.getNameServiceClient()).thenReturn(nameServiceClient);
        lenient().when(cifsContext.getConfig()).thenReturn(configuration);

            log.debug("Exception in disconnect", e);
        } finally {
            this.socket = null;
            this.digest = null;
            this.tconHostName = null;
            this.transportContext.getTransportPool().removeTransport(this);
        }
        return wasInUse;
    }

    @Override
    protected long makeKey(final Request request) throws IOException {
        long m = this.mid.incrementAndGet() - 1;