assertTrue(validator.isValid(null, context));
    }

    public void test_isValid_blankValue() {
        final ConstraintValidatorContext context = null;
        assertTrue(validator.isValid(" ", context));
        assertTrue(validator.isValid("   ", context));
        assertTrue(validator.isValid("\t", context));
        assertTrue(validator.isValid("\n", context));
    }

    }

    /**
     * Test isValid() when the handle is valid.
     */
    @Test
    void testIsValid_whenValid() {
        when(smbFileHandle.isValid()).thenReturn(true);
        assertTrue(smbFileHandle.isValid(), "isValid should return true when the handle is valid.");
        verify(smbFileHandle, times(1)).isValid();
    }

    /**
     * Test isValid() when the handle is invalid.
     */
    @Test

    }

    @Test
    @DisplayName("Test isValid returns false for invalid negotiation")
    void testIsValidReturnsFalse() {
        // Arrange
        when(negotiationResponse.isValid(cifsContext, negotiationRequest)).thenReturn(false);

        // Act
        boolean result = negotiationResponse.isValid(cifsContext, negotiationRequest);

        // Assert

        when(mockFileHandle.isValid()).thenReturn(false);
        assertFalse(outputStream.isOpen());
    }

    @Test
    void testWriteAfterClose() throws IOException, CIFSException {
        // Given
        when(mockTreeHandle.isSMB2()).thenReturn(true);
        when(mockTreeHandle.getSendBufferSize()).thenReturn(65536);
        when(mockFileHandle.isValid()).thenReturn(true);

        validator.initialize(annotation);

        // Test that the method can be called (even if context handling is complex)
        try {
            final boolean result = validator.isValid("test", null);
            assertNotNull("isValid should return a boolean result", Boolean.valueOf(result));
        } catch (final NullPointerException e) {
            // This is expected if the implementation requires a non-null context

                    this.currentHash = newHash.clone();
                }
            }
        }

        public boolean isValid() {
            return isValid;
        }

        public void invalidate() {
            this.isValid = false;
            // Clear sensitive data
            synchronized (hashLock) {
                Arrays.fill(currentHash, (byte) 0);
            }

        assertTrue(h.isValid());

        // Tree id change makes it invalid
        when(tree.getTreeId()).thenReturn(11L);
        assertFalse(h.isValid());

        // Connected=false makes it invalid
        when(tree.getTreeId()).thenReturn(10L);
        when(tree.isConnected()).thenReturn(false);
        assertFalse(h.isValid());

        // Mark closed makes it invalid

    @Mock
    SmbTreeHandleImpl tree;

    // Prepare SMB2 flow with a given response
    private void setupSmb2(NotifyResponse resp, byte[] fileId) throws Exception {
        when(handle.isValid()).thenReturn(true);
        when(handle.getTree()).thenReturn(tree);
        when(tree.isSMB2()).thenReturn(true);
        when(tree.getConfig()).thenReturn(mock(Configuration.class));

        // When
        boolean valid = response.isValid(mockContext, mockRequest);

        // Then
        assertTrue(valid);
        assertEquals(DialectVersion.SMB311, response.getSelectedDialect());
    }

    @Test
    @DisplayName("Should fail validation when not received")
    void testIsValidNotReceived() {
        // When
        boolean valid = response.isValid(mockContext, mockRequest);

        // Then

     * @throws SmbException
     */
    public int getFid() throws SmbException {
        if (!isValid()) {
            throw new SmbException("Descriptor is no longer valid");
        }
        return this.fid;
    }

    public byte[] getFileId() throws SmbException {
        if (!isValid()) {
            throw new SmbException("Descriptor is no longer valid");
        }
        return this.fileId;