CharBuffer buf2 = CharBuffer.allocate(expected.length());
    assertEquals(expected.length() == 0 ? -1 : expected.length(), reader.read(buf2));
    Java8Compatibility.flip(buf2);
    assertEquals(expected, buf2.toString());
    assertFullyRead(reader);

    // read in chunks to fixed CharBuffer
    reader = new CharSequenceReader(charSequence);
    buf2 = CharBuffer.allocate(5);
    builder = new StringBuilder();