executor.shutdown();

        // Then - No unexpected exceptions
        assertTrue(exceptions.isEmpty(), "No unexpected exceptions should occur");
    }

    /**
     * Test that CopyOnWriteArrayList prevents ConcurrentModificationException.
     */
    @Test
    public void testNoConcurrentModificationException() throws Exception {
        // Given

   * @param exceptionType the exception type that triggers use of {@code fallback}. The exception
   *     type is matched against the input's exception. "The input's exception" means the cause of
   *     the {@link ExecutionException} thrown by {@code input.get()} or, if {@code get()} throws a
   *     different kind of exception, that exception itself. To avoid hiding bugs and other

  final Collection<? extends Throwable> exceptions;

  private ClusterException(Collection<? extends Throwable> exceptions) {
    super(
        exceptions.size() + " exceptions were thrown. The first exception is listed as a cause.",
        exceptions.iterator().next());
    ArrayList<? extends Throwable> temp = new ArrayList<>(exceptions);
    this.exceptions = Collections.unmodifiableCollection(temp);
  }

         * @param request the request data
         * @param exceptionList the list of exceptions that occurred during retries
         */
        void onRequestEnd(FaultTolerantClient client, RequestData request, List<Exception> exceptionList);

        /**
         * Called when an exception occurs during a request attempt.
         *
         * @param client the fault-tolerant client

        assertNotNull(exception.getCause());
        assertEquals(cause, exception.getCause());
        assertEquals("Root cause exception", exception.getCause().getMessage());
    }

    public void test_constructorWithNullMessage() {
        // Test constructor with null message
        GsaConfigException exception = new GsaConfigException(null);

        assertNotNull(exception);

        } catch (Exception e) {
            fail("Should not throw exception: " + e.getMessage());
        }
    }

    public void test_sendMail_withEmptyInfoMap() {
        Map<String, String> infoMap = new HashMap<>();

        try {
            crawler.sendMail(infoMap);
        } catch (Exception e) {
            fail("Should not throw exception with empty map: " + e.getMessage());
        }

        @DisplayName("Should handle deeply nested exceptions")
        void testToStringWithNestedExceptions() {
            Exception innermost = new IOException("Innermost exception");
            Exception middle = new RuntimeException("Middle exception", innermost);
            Exception rootCause = new IllegalStateException("Outer exception", middle);
            TransportException exception = new TransportException("Transport failed", rootCause);

        // Try to execute - should be blocked with CIFSException
        CIFSException exception = assertThrows(CIFSException.class, () -> {
            circuitBreaker.executeWithCircuitBreaker(() -> "should not execute");
        }, "Circuit breaker should throw CIFSException when open");

        assertTrue(exception.getMessage().contains("Circuit breaker 'test' is open"), "Exception message should indicate circuit is open");
    }

    @Test

        assertNotNull(exception);
        assertEquals(message, exception.getMessage());
        assertNotNull(exception.getCause());
        assertEquals(middleCause, exception.getCause());
        assertEquals("Middle cause", exception.getCause().getMessage());
        assertNotNull(exception.getCause().getCause());
        assertEquals(rootCause, exception.getCause().getCause());

        assertTrue(exception instanceof RuntimeException);
        assertTrue(exception instanceof Exception);
        assertTrue(exception instanceof Throwable);
    }

    public void test_serialization() {
        // Test that the exception has serialVersionUID defined
        JobNotFoundException exception = new JobNotFoundException("test");