@Test
public void testRequestSetsRangeHeader() throws HttpDataSourceException {

  testDataSpec = new DataSpec(Uri.parse(TEST_URL), 1000, 5000, null);
  mockResponseStartSuccess();
  dataSourceUnderTest.open(testDataSpec);
  // The header value to add is current position to current position + length - 1.
  verify(mockUrlRequestBuilder).addHeader("Range", "bytes=1000-5999");
}