@Test public void getAll_extracted() {

  injector.inject(context, request);
  request.put("x-amzn-trace-id", awsTraceId);
  TraceContextOrSamplingFlags extracted = extractor.extract(request);
  assertThat(ExtraFieldPropagation.getAll(extracted))
    .hasSize(1)
    .containsEntry("x-amzn-trace-id", awsTraceId);
}