class InvalidInputs {
        @Test
        @DisplayName("getSigningKey throws when unavailable")
        void testGetSigningKeyThrows() {
            DummySSPContext ctx = new DummySSPContext(null, false, null, null, 0, false);
            CIFSException ex = assertThrows(CIFSException.class, ctx::getSigningKey);
            assertTrue(ex.getMessage().contains("signing key"));
        }

        @Test

    }

    @Test
    @DisplayName("getSigningKey delegates to underlying mechanism context")
    void testGetSigningKeyDelegates() throws Exception {
        SpnegoContext ctx = newContext();
        byte[] key = new byte[] { 1, 2, 3 };
        when(this.mechContext.getSigningKey()).thenReturn(key);
        assertSame(key, ctx.getSigningKey());
        verify(this.mechContext, times(1)).getSigningKey();
    }

    @Test

     */
    byte[] getSessionKey();

    /**
     * Gets the signing key for SMB2/3
     *
     * @return the signing key or null if not available
     */
    byte[] getSigningKey();

    /**
     * Validates authentication credentials
     *
     * @return true if credentials are valid
     */
    boolean validateCredentials();

    /**

    /**
     * Gets the signing key for the session.
     * @return the signing key for the session
     * @throws CIFSException if an error occurs retrieving the signing key
     */
    byte[] getSigningKey() throws CIFSException;

    /**
     * Checks whether the security context is established.
     * @return whether the context is established
     */
    boolean isEstablished();

    /**

    public String getNetbiosName() {
        return null;
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.smb.SSPContext#getSigningKey()
     */
    @Override
    public byte[] getSigningKey() throws CIFSException {
        return this.mechContext.getSigningKey();
    }

    /**
     * Initialize the GSSContext to provide SPNEGO feature.
     *
     * @param inputBuf
     * @param offset

     */
    @Override
    public String getNetbiosName() {
        return null;
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.smb.SSPContext#getSigningKey()
     */
    @Override
    public byte[] getSigningKey() throws SmbException {
        /*
         * The kerberos session key is not accessible via the JGSS API. IBM and
         * Oracle both implement a similar API to make an ExtendedGSSContext

		cr.seedDate.Format(iso8601Format) + "\n" +
		getScope(cr.seedDate, cr.region) + "\n" +
		cr.seedSignature + "\n" +
		emptySHA256 + "\n" +
		hashedChunk

	// Get hmac signing key.
	signingKey := getSigningKey(cr.cred.SecretKey, cr.seedDate, cr.region, serviceS3)

	// Calculate signature.
	newSignature := getSignature(signingKey, stringToSign)

	return newSignature
}

        return serverChallenge;
    }

    /**
     * Gets the signing key for message authentication.
     * @return the signing key bytes
     */
    public byte[] getSigningKey() {
        return signingKey;
    }

    /**
     * Gets the NetBIOS name of the remote server.
     * @return the NetBIOS name
     */
    public String getNetbiosName() {

    void getNetbiosName_null() {
        assertNull(ctx.getNetbiosName());
    }

    @Test
    @DisplayName("getSigningKey throws when ExtendedGSSContext not implemented")
    void getSigningKey_notImplementedByGSSContext() {
        SmbException ex = assertThrows(SmbException.class, () -> ctx.getSigningKey());
        assertTrue(ex.getMessage().contains("ExtendedGSSContext is not implemented"));
    }

    @Test

     * @return the server's challenge
     */
    public byte[] getServerChallenge() {
        return this.serverChallenge;
    }

    @Override
    public byte[] getSigningKey() {
        return this.masterKey;
    }

    @Override
    public String getNetbiosName() {
        return this.netbiosName;
    }

    /**