@Test
public void multipleHeadersSameValue() throws Exception {

  final Header header = BatchParserCommon.consumeHeaders(toLineList(
      "Content-Id: 1" + CRLF,
      "Content-Id: 1" + CRLF,
      "content-type: Application/http" + CRLF,
      "content-transfer-encoding: Binary" + CRLF));
  assertNotNull(header);
  final List<String> contentIdHeaders = header.getHeaders(HttpHeader.CONTENT_ID);
  assertNotNull(contentIdHeaders);
  assertEquals(1, contentIdHeaders.size());
  assertEquals("1", contentIdHeaders.get(0));
}