private static final String BOUNDARY = "batch_123";
@Test
public void testSimpleBatch() throws Exception {
List<BatchPart> batch = new ArrayList<BatchPart>();
BatchPart request = BatchQueryPart.method(GET).uri("$metadata").build();
batch.add(request);
InputStream body = EntityProvider.writeBatchRequest(batch, BOUNDARY);
String batchRequestBody = StringHelper.inputStreamToString(body, true);
checkMimeHeaders(batchRequestBody);