@Test
public void testExtractInvalidHeaders() {

    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);
}