}

  public void testSkipNulls() {
    Joiner skipNulls = J.skipNulls();
    checkNoOutput(skipNulls, iterable);
    checkNoOutput(skipNulls, iterableNull);
    checkNoOutput(skipNulls, iterableNullNull);
    checkNoOutput(skipNulls, iterableFourNulls);
    checkResult(skipNulls, iterable1, "1");
    checkResult(skipNulls, iterable12, "1-2");
    checkResult(skipNulls, iterable123, "1-2-3");

  }

  public void testSkipNulls() {
    Joiner skipNulls = J.skipNulls();
    checkNoOutput(skipNulls, iterable);
    checkNoOutput(skipNulls, iterableNull);
    checkNoOutput(skipNulls, iterableNullNull);
    checkNoOutput(skipNulls, iterableFourNulls);
    checkResult(skipNulls, iterable1, "1");
    checkResult(skipNulls, iterable12, "1-2");
    checkResult(skipNulls, iterable123, "1-2-3");

   *   <li>Inequality check is not performed against state mutation methods such as {@link
   *       List#add}, or functional update methods such as {@link
   *       com.google.common.base.Joiner#skipNulls}.
   * </ul>
   *
   * <p>Note that constructors taking a builder object cannot be tested effectively because
   * semantics of builder can be arbitrarily complex. Still, a factory class can be created in the

    assertThrows(EOFException.class, () -> CharStreams.skipFully(reader, 6));
  }

  public void testSkipFully() throws IOException {
    String testString = "abcdef";
    Reader reader = new StringReader(testString);

    assertEquals(testString.charAt(0), reader.read());
    CharStreams.skipFully(reader, 1);
    assertEquals(testString.charAt(2), reader.read());
    CharStreams.skipFully(reader, 2);

    assertThrows(EOFException.class, () -> CharStreams.skipFully(reader, 6));
  }

  public void testSkipFully() throws IOException {
    String testString = "abcdef";
    Reader reader = new StringReader(testString);

    assertEquals(testString.charAt(0), reader.read());
    CharStreams.skipFully(reader, 1);
    assertEquals(testString.charAt(2), reader.read());
    CharStreams.skipFully(reader, 2);

                      }
                    })
                .iterator());
    assertEquals(0, multi.skip(-1));
    assertEquals(0, multi.skip(-1));
    assertEquals(0, multi.skip(0));
    ByteStreams.skipFully(multi, 20);
    assertEquals(20, multi.read());
  }

  public void testReadSingle_noStackOverflow() throws IOException {
    // https://github.com/google/guava/issues/2996

                      }
                    })
                .iterator());
    assertEquals(0, multi.skip(-1));
    assertEquals(0, multi.skip(-1));
    assertEquals(0, multi.skip(0));
    ByteStreams.skipFully(multi, 20);
    assertEquals(20, multi.read());
  }

  public void testReadSingle_noStackOverflow() throws IOException {
    // https://github.com/google/guava/issues/2996

   * @param n the number of characters to skip
   * @throws EOFException if this stream reaches the end before skipping all the characters
   * @throws IOException if an I/O error occurs
   */
  public static void skipFully(Reader reader, long n) throws IOException {
    checkNotNull(reader);
    while (n > 0) {
      long amt = reader.skip(n);
      if (amt == 0) {
        throw new EOFException();
      }
      n -= amt;

   * @throws EOFException if this stream reaches the end before skipping all the bytes
   * @throws IOException if an I/O error occurs, or the stream does not support skipping
   */
  public static void skipFully(InputStream in, long n) throws IOException {
    long skipped = skipUpTo(in, n);
    if (skipped < n) {
      throw new EOFException(