@Test
public void testExtractEmptyHeaders() {

    Map<String, String> headers = new HashMap<>();
    headers.put("ot-tracer-spanid", "");
    headers.put("ot-tracer-traceId", "");
    TextMapPropagator subject = new TextMapPropagator();
    SpanContext spanContext = subject.extract(new TextMapExtractAdapter(headers));
    assertNull(spanContext);
}