}

    @Test
    public void test_inheritance() {
        DocList docList = new DocList();

        assertTrue(docList instanceof java.util.ArrayList);
        assertTrue(docList instanceof java.util.List);
        assertTrue(docList instanceof java.util.Collection);
    }

        // Verify that ContentNotFoundException is an instance of FessSystemException
        String parentUrl = "http://example.com/parent";
        String url = "http://example.com/child";
        ContentNotFoundException exception = new ContentNotFoundException(parentUrl, url);

        assertTrue(exception instanceof FessSystemException);
        assertTrue(exception instanceof RuntimeException);
    }

    @Test

        final String mimeType;
        if (response instanceof HtmlResponse) {
            mimeType = "text/html";
        } else if (response instanceof JsonResponse) {
            mimeType = "application/json";
        } else if (response instanceof XmlResponse) {
            mimeType = "text/xml";
        } else if (response instanceof StreamResponse) {
            mimeType = "application/octet-stream";

        Object deserialized = serializer.fromBinaryToObject(serialized);
        assertNotNull(deserialized, "Deserialized object should not be null");
        assertTrue("Deserialized object should be a List", deserialized instanceof List);

        @SuppressWarnings("unchecked")
        List<String> deserializedList = (List<String>) deserialized;
        assertEquals("List size should match", original.size(), deserializedList.size());

   */
  public static Function<Object, String> toStringFunction() {
    return ToStringFunction.INSTANCE;
  }

  // enum singleton pattern
  private enum ToStringFunction implements Function<Object, String> {
    INSTANCE;

    @Override
    public String apply(Object o) {
      checkNotNull(o); // eager for GWT.
      return o.toString();
    }

    @Override

        ServletRuntimeException runtimeException = new ServletRuntimeException(servletException);

        // Verify it's an instance of RuntimeException
        assertTrue(runtimeException instanceof RuntimeException);
        assertTrue(runtimeException instanceof Exception);
        assertTrue(runtimeException instanceof Throwable);
    }

    @Test
    public void test_stackTrace() {

  protected void tearDown() throws Exception {
    Throwable t = threadFailure.getAndSet(null);
    if (t != null) {
      if (t instanceof Error) {
        throw (Error) t;
      } else if (t instanceof RuntimeException) {
        throw (RuntimeException) t;
      } else if (t instanceof Exception) {
        throw (Exception) t;
      } else {
        AssertionFailedError afe = new AssertionFailedError(t.toString());

            return null;
        }
        if (src.getClass() == Date.class) {
            return (Date) src;
        }
        if (src instanceof Date) {
            return new Date(((Date) src).getTime());
        }
        if (src instanceof Calendar) {
            return new Date(((Calendar) src).getTimeInMillis());
        }
        final String str = src.toString();
        if (isEmpty(str)) {

        if (keyObj instanceof final UrlQueue<?> urlQueue) {
            return escapeValue(urlQueue.getUrl());
        }
        if (keyObj instanceof final StatsKeyObject statsKey) {
            return escapeValue(statsKey.getUrl());
        }
        if (keyObj instanceof final String key) {
            return escapeValue(key);
        }
        if (keyObj instanceof final Number key) {

            return null;
        }
        if (src.getClass() == Date.class) {
            return (Date) src;
        }
        if (src instanceof Date) {
            return new Date(((Date) src).getTime());
        }
        if (src instanceof Calendar) {
            return new Date(((Calendar) src).getTimeInMillis());
        }
        final String str = src.toString();
        if (isEmpty(str)) {