SpnegoContext ctx = newContext();

        // Invalid first byte should be rejected by token parsing
        CIFSException ex = assertThrows(CIFSException.class, () -> ctx.initSecContext(new byte[] { firstByte }, 0, 1));
        assertEquals("Invalid token", ex.getMessage());

        // Ensure mechContext was not engaged due to early failure

        CIFSException boom = new CIFSException("tree-fail");
        when(handle.ensureTreeConnected()).thenThrow(boom);

        // Act + Assert
        CIFSException ex = assertThrows(CIFSException.class, out::ensureTreeConnected);
        assertEquals("tree-fail", ex.getMessage());
        verify(handle, times(1)).ensureTreeConnected();
    }

    @Test
    @DisplayName("ensureOpen delegates and returns the file handle")

            // Act + Assert
            SmbException ex = assertThrows(SmbException.class, () -> SmbEnumerationUtil.doShareEnum(parent, "*", 0, null, null));

            // Assert message indicates which validation failed
            if (expectDirSlashMsg) {
                assertTrue(ex.getMessage().contains("directory must end with '/'"),
                        "Expected trailing slash message, was: " + ex.getMessage());
            } else {

    void hasCapability_throws() throws SmbException {
        doThrow(new SmbException("capability check failed")).when(transport).hasCapability(eq(42));
        SmbException ex = assertThrows(SmbException.class, () -> transport.hasCapability(42));
        assertTrue(ex.getMessage().contains("failed"));
        verify(transport).hasCapability(42);
    }

    // Edge: disconnected status toggles
    @ParameterizedTest

        byte[] data = new byte[] { 0 };
        when(gssContext.getMIC(any(), anyInt(), anyInt(), any())).thenThrow(new GSSException(GSSException.FAILURE));

        CIFSException ex = assertThrows(CIFSException.class, () -> ctx.calculateMIC(data));
        assertTrue(ex.getMessage().contains("Failed to calculate MIC"));
    }

    @Test
    @DisplayName("calculateMIC with null data throws NPE")
    void calculateMIC_nullData() {

                        } catch (final Exception ex) {}
                        if (handlerClass == null) {
                            handlerClass = ClassLoader.getSystemClassLoader().loadClass(className);
                        }
                        handler = (URLStreamHandler) handlerClass.newInstance();
                        break;
                    } catch (final Exception ex) {}
                }
            }

        assertArgumentNotNull("field", field);

        try {
            return (T) field.get(target);
        } catch (final IllegalAccessException ex) {
            throw new IllegalAccessRuntimeException(field.getDeclaringClass(), ex);
        }
    }

    /**
     * Returns the value of a {@literal static} {@link Field} as an int.
     *
     * @param field the field (must not be {@literal null})

        SmbException ex =
                assertThrows(SmbException.class, () -> new DirFileEntryEnumIterator1(tree, parent, "*", (ResourceNameFilter) null, 0));
        assertTrue(ex.getMessage().contains("UNC must end with '\\'"), "Actual message: " + ex.getMessage());
        verify(tree, times(1)).acquire();
        verify(tree, times(1)).release();
    }

                return k.getEncoded();
            } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException ex) {
                throw new SmbException("Failed to query Kerberos session key from ExtendedGSSContext", ex);
            }
        }
        throw new SmbException("ExtendedGSSContext is not implemented by GSSContext");
    }

    @Override

    ListeningScheduledExecutorService service = listeningDecorator(delegate);
    RuntimeException ex = new RuntimeException();
    ListenableFuture<?> future = service.schedule(new ThrowingRunnable(0, ex), 1, MILLISECONDS);
    assertExecutionException(future, ex);
    assertEquals(0, delegate.getQueue().size());
  }

  public void testListeningDecorator_schedulePeriodic() throws Exception {