when(mockCifsContext.getConfig()).thenReturn(mockConfig);

        // Mock credentials to prevent NPE
        when(mockCredentials.getUserDomain()).thenReturn("DOMAIN");
        when(mockCifsContext.getCredentials()).thenReturn(mockCredentials);

        // Create URL handler
        Handler urlHandler = new jcifs.smb.Handler(mockCifsContext);
        when(mockCifsContext.getUrlHandler()).thenReturn(urlHandler);

    void getSmbSession_createAndReuse() {
        // Arrange: minimal credentials chain so SmbSessionImpl constructor succeeds
        CredentialsInternal creds = mock(CredentialsInternal.class);
        when(ctx.getCredentials()).thenReturn(creds);
        when(creds.unwrap(CredentialsInternal.class)).thenReturn(creds);
        when(creds.clone()).thenReturn(creds);

        assertEquals(0, transport.getNumSessions());

            throw new SmbException("Service is NULL");
        }

        if (transport.getContext().getConfig().isIpcSigningEnforced() && ("IPC$".equals(this.getShare()) || "IPC".equals(rsvc))
                && !sess.getCredentials().isAnonymous() && sess.getDigest() == null) {
            throw new SmbException("IPC signing is enforced, but no signing is available");
        }

        this.service = rsvc;

    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();
            return trans.getServerEncryptionKey();

     *
     * @see jcifs.smb.SmbResourceLocatorInternal#shouldForceSigning()
     */
    @Override
    public boolean shouldForceSigning() {
        return this.ctx.getConfig().isIpcSigningEnforced() && !this.ctx.getCredentials().isAnonymous() && isIPC();
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.SmbResourceLocator#isIPC()
     */
    @Override
    public boolean isIPC() {

                }
                return ssn.acquire();
            }
            if (log.isTraceEnabled()) {
                log.trace("Existing session " + ssn + " does not match " + tf.getCredentials());
            }
        }

        /* logoff old sessions */
        if (tf.getConfig().getSessionTimeout() > 0 && this.sessionExpiration < (now = System.currentTimeMillis())) {