void setUp() throws Exception {
        // Common, safe defaults for collaborators
        when(mockHandle.isValid()).thenReturn(true);
        when(mockHandle.acquire()).thenReturn(mockHandle);
        when(mockHandle.getTree()).thenReturn(mockTree);
        when(mockHandle.getFileId()).thenReturn(new byte[16]);

        when(mockTree.getReceiveBufferSize()).thenReturn(0x10000);
        when(mockTree.getMaximumBufferSize()).thenReturn(0x10000);

            return;
        }

        if (this.tmp == null) {
            throw new IOException("Bad file descriptor");
        }

        try (SmbFileHandleImpl fh = ensureOpen(); SmbTreeHandleImpl th = fh.getTree()) {
            if (log.isDebugEnabled()) {
                log.debug("write: fid=" + fh + ",off=" + off + ",len=" + len + ",fp=" + this.fp);
            }

            int w;
            do {

        if (this.tmp == null) {
            throw new IOException("Bad file descriptor");
        }
        // ensure file is open
        try (SmbFileHandleImpl fd = ensureOpen(); SmbTreeHandleImpl th = fd.getTree()) {

            if (log.isTraceEnabled()) {
                log.trace("read: fid=" + fd + ",off=" + off + ",len=" + len);
            }

            final int type = this.file.getType();
            int r, n;

    private Smb2WriteResponse mockWriteResponse;

    private SmbFileOutputStream outputStream;

    @BeforeEach
    void setUp() {
        // Common setup for most tests
        lenient().when(mockFileHandle.getTree()).thenReturn(mockTreeHandle);
        lenient().when(mockTreeHandle.getConfig()).thenReturn(mockConfig);
    }

    @Test
    void testWriteSingleByte() throws IOException, CIFSException {
        // Given

                    request.setWatchTree(false);  // Non-recursive for now
                    
                    Smb2ChangeNotifyResponse response = (Smb2ChangeNotifyResponse) 
                        handle.directoryFile.getTree().send(request);
                    
                    if (response.isSuccess()) {
                        processChangeNotification(handle, response);
                    }