assertEquals(ASCII.length(), CharStreams.exhaust(reader));
    assertEquals(-1, reader.read());
    assertEquals(0, CharStreams.exhaust(reader));

    Reader empty = new StringReader("");
    assertEquals(0, CharStreams.exhaust(empty));
    assertEquals(-1, empty.read());
  }

  public void testExhaust_readable() throws IOException {
    CharBuffer buf = CharBuffer.wrap(ASCII);

            public List<DataConfig> getAllDataConfigList() {
                return new ArrayList<>(); // Always return empty for fast tests
            }

            @Override
            public List<DataConfig> getDataConfigListByIds(List<String> configIdList) {
                return new ArrayList<>(); // Always return empty for fast tests
            }

            public String store(String sessionId, DataConfig dataConfig) {

                return OptionalEntity.empty();
            }
        }, WebConfigService.class.getCanonicalName());

        assertTrue(crawlingConfigHelper.getPipeline("W1").isEmpty());
    }

    public void test_getPipeline_withEmptyStringPipeline() {
        // Register service that returns empty string pipeline
        ComponentUtil.register(new WebConfigService() {

     */
    public OptionalEntity<CharMappingFile> getCharMappingFile(final String dictId) {
        return dictionaryManager.getDictionaryFile(dictId)
                .filter(CharMappingFile.class::isInstance)
                .map(file -> OptionalEntity.of((CharMappingFile) file))
                .orElse(OptionalEntity.empty());
    }

    /**

import java.util.Set;
import java.util.concurrent.ExecutionException;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * {@link LoadingCache} tests that deal with empty caches.
 *
 * @author mike nonemacher
 */

@NullUnmarked
public class EmptyCachesTest extends TestCase {

  public void testEmpty() {
    for (LoadingCache<Object, Object> cache : caches()) {

    /**
     * Decodes MIME-encoded text.
     *
     * @param value the encoded text to decode
     * @return the decoded text or empty string if decoding fails
     */
    protected String getDecodeText(final String value) {
        if (value == null) {
            return StringUtil.EMPTY;
        }
        try {
            return MimeUtility.decodeText(value);
        } catch (final UnsupportedEncodingException e) {

      throw closer.rethrow(e);
    } finally {
      closer.close();
    }
  }

  /**
   * Reads all the lines of this source as a list of strings. The returned list will be empty if
   * this source is empty.
   *
   * <p>Like {@link BufferedReader#readLine()}, this method considers a line to be a sequence of
   * text that is terminated by (but does not include) one of {@code \r\n}, {@code \r} or {@code

      throw closer.rethrow(e);
    } finally {
      closer.close();
    }
  }

  /**
   * Reads all the lines of this source as a list of strings. The returned list will be empty if
   * this source is empty.
   *
   * <p>Like {@link BufferedReader#readLine()}, this method considers a line to be a sequence of
   * text that is terminated by (but does not include) one of {@code \r\n}, {@code \r} or {@code

     *
     * @param dataset the dataset to do the calculation on, which must be non-empty, and which will
     *     be arbitrarily reordered by this method call
     * @return the quantile value
     */
    public double computeInPlace(double... dataset) {
      checkArgument(dataset.length > 0, "Cannot calculate quantiles of an empty dataset");
      if (containsNaN(dataset)) {
        return NaN;
      }

  /**
   * Trailers received when the response body became exhausted.
   *
   * If the response body was successfully read until the end, this is the headers that followed,
   * or empty headers if there were none that followed.
   *
   * If the response body was closed prematurely or failed with an error, this will be the sentinel