// Create a mock exception that could have circular reference
            Exception rootCause = mock(Exception.class);
            when(rootCause.getMessage()).thenReturn("Mocked exception");

            TransportException exception = new TransportException("Test", rootCause);

            assertEquals(rootCause, exception.getRootCause());
            // toString should not cause infinite loop

 * A generator of {@code TestSuite} instances for testing {@code CharSource} implementations.
 * Generates tests of all methods on a {@code CharSource} given various inputs the source is
 * expected to contain.
 *
 * @author Colin Decker
 */
@AndroidIncompatible // TODO(b/230620681): Make this available (even though we won't run it).
@NullUnmarked
public class CharSourceTester extends SourceSinkTester<CharSource, String, CharSourceFactory> {

import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Base test case class for I/O tests.
 *
 * @author Chris Nokleberg
 * @author Colin Decker
 */
@NullUnmarked
public abstract class IoTestCase extends TestCase {

  private static final Logger logger = Logger.getLogger(IoTestCase.class.getName());

  static final String I18N =

 * character encoding} using {@link ByteSink#asCharSink(Charset)}. Characters written to the
 * resulting {@code CharSink} will written to the {@code ByteSink} as encoded bytes.
 *
 * @since 14.0
 * @author Colin Decker
 */
@J2ktIncompatible
@GwtIncompatible
public abstract class CharSink {

  /** Constructor for use by subclasses. */
  protected CharSink() {}

  /**

 * controls the order in which events are dispatched, while the executor controls how (i.e. on which
 * thread) the subscriber is actually called when an event is dispatched to it.
 *
 * @author Colin Decker
 */
abstract class Dispatcher {

  /**
   * Returns a dispatcher that queues events that are posted reentrantly on a thread that is already

int maxDepth = -1               // Max depth (-1 = unlimited)
long maxAccessCount = 0         // Max URLs (0 = unlimited)
```

### CrawlerThread (`CrawlerThread.java`)

Worker thread for crawling.

**Flow**: Poll URL → Validate → Get client → Delay → Check last-modified → Execute → Process → Extract children → Queue children → Delay

### CrawlerClientFactory

    @Mock
    Configuration mockCfg;

    // Provides a fresh handler instance for tests
    private Handler newHandler() {
        return new Handler();
    }

    // Provides a handler wired with a mocked CIFSContext
    private Handler newHandlerWith(CIFSContext ctx) {
        return new Handler(ctx);
    }

    @Test
    @DisplayName("getDefaultPort returns SMB default port")
    void testGetDefaultPort() {

        // Resource errors
        OUT_OF_MEMORY("Out of memory", ErrorCategory.RESOURCE, true), TOO_MANY_SESSIONS("Too many sessions", ErrorCategory.RESOURCE,
                true), RESOURCE_LOCKED("Resource is locked", ErrorCategory.RESOURCE, true),

        // Transient errors
        BUSY("Server busy", ErrorCategory.TRANSIENT, true), TRY_AGAIN("Try again later", ErrorCategory.TRANSIENT,

efficiently makes your stuff load faster and saves bandwidth.

OkHttp is an HTTP client that’s efficient by default:

 * HTTP/2 support allows all requests to the same host to share a socket.
 * Connection pooling reduces request latency (if HTTP/2 isn’t available).
 * Transparent GZIP shrinks download sizes.
 * Response caching avoids the network completely for repeat requests.

        when(mockDelegate.hasNext()).thenReturn(true, true, true, false);
        when(mockDelegate.next()).thenReturn(mockFileEntry1, mockFileEntry2, mockFileEntry3);

        // Create a simple test iterator that returns mocked resources
        DirFileEntryAdapterIterator iterator = new DirFileEntryAdapterIterator(mockParent, mockDelegate, null) {
            @Override
            protected SmbResource adapt(FileEntry e) {