import java.util.concurrent.ExecutionException;
import junit.framework.Assert;

/**
 * A simple mock implementation of {@code Runnable} that can be used for testing ListenableFutures.
 *
 * @author Nishant Thakkar
 * @since 10.0
 */
@GwtIncompatible
public class MockFutureListener implements Runnable {
  private final CountDownLatch countDownLatch;
  private final ListenableFuture<?> future;

   */
  @GuardedBy("lock")
  private int runningTasks = 0;

  @GuardedBy("lock")
  private boolean shutdown = false;

  @Override
  public void execute(Runnable command) {
    startTask();
    try {
      command.run();
    } finally {
      endTask();
    }
  }

  @Override
  public boolean isShutdown() {
    synchronized (lock) {
      return shutdown;

 * For restrictions, please refer to the documentation of the then() method.
 */
public interface ListenableFuture<V extends @Nullable Object> extends Future<V>, IThenable<V> {
  void addListener(Runnable listener, Executor executor);

  /** Note that this method is not expected to be overridden. */
  @JsMethod
  @Override
  default <R extends @Nullable Object> IThenable<R> then(

    validations:
      required: true

  - type: textarea
    id: what-did-you-do
    attributes:
      label: "What did you do?"
      description: "If possible, provide a recipe for reproducing the error. A complete runnable program is good. A link on [go.dev/play](https://go.dev/play) is best."
    validations:
      required: true

  - type: textarea
    id: actual-behavior
    attributes:
      label: "What did you see happen?"

  }

  @CanIgnoreReturnValue
  static <T extends Throwable> T assertThrows(
      Class<T> expectedThrowable, ThrowingRunnable runnable) {
    return doAssertThrows(
        expectedThrowable,
        () -> {
          runnable.run();
          return null;
        },
        /* userPassedSupplier= */ false);
  }

  private static <T extends Throwable> T doAssertThrows(

 * @author Charles Fry
 */
@NullUnmarked
public class CacheLoaderTest extends TestCase {

  private static class QueuingExecutor implements Executor {
    private final Deque<Runnable> tasks = new ArrayDeque<>();

    @Override
    public void execute(Runnable task) {
      tasks.add(task);
    }

    private void runNext() {
      tasks.removeFirst().run();
    }
  }

  public void testAsyncReload() throws Exception {

   */
  @GuardedBy("lock")
  private int runningTasks = 0;

  @GuardedBy("lock")
  private boolean shutdown = false;

  @Override
  public void execute(Runnable command) {
    startTask();
    try {
      command.run();
    } finally {
      endTask();
    }
  }

  @Override
  public boolean isShutdown() {
    synchronized (lock) {
      return shutdown;

  }

  @CanIgnoreReturnValue
  static <T extends Throwable> T assertThrows(
      Class<T> expectedThrowable, ThrowingRunnable runnable) {
    return doAssertThrows(
        expectedThrowable,
        () -> {
          runnable.run();
          return null;
        },
        /* userPassedSupplier= */ false);
  }

  private static <T extends Throwable> T doAssertThrows(

 *
 * {@snippet :
 * final String name = ...;
 * inFlight.add(name);
 * ListenableFuture<Result> future = service.query(name);
 * future.addListener(new Runnable() {
 *   public void run() {
 *     processedCount.incrementAndGet();
 *     inFlight.remove(name);
 *     lastProcessed.set(name);
 *     logger.info("Done with {0}", name);
 *   }
 * }, executor);
 * }
 *

        assertEquals(currentTime, t.ltime, "ltime should be mutable");
    }

    @Test
    @DisplayName("TestLocking implements Runnable")
    void testImplementsRunnable() {
        TestLocking t = new TestLocking();
        assertTrue(t instanceof Runnable, "TestLocking should implement Runnable");
    }

    @Test
    @DisplayName("run method handles null URL gracefully")
    void testRunWithNullUrl() {