### Question:
HeadersImpl implements Headers { @Override public long getContentLength() { final String value = getFirst(CONTENT_LENGTH); return value == null ? -1 : Long.parseLong(value); } private  HeadersImpl(boolean readOnly);  HeadersImpl();  HeadersImpl(Headers headers, boolean readOnly); @Override List<String> get(String headerName); @Override void add(String headerName, String value); @Override void put(String headerName, String value); @Override String getFirst(String headerName); @Override Set<String> headerNames(); @Override long getContentLength(); @Override void setContentLength(long contentLength); @Override ContentType getContentType(); @Override void setContentType(ContentType contentType);  }### Answer:
@Test public void shouldReturnMinusOneForUnknownContentLength() { final HeadersImpl headers = new HeadersImpl(); assertEquals(-1L, headers.getContentLength()); }