@Test
public void testExtractSpanContext() {

    HttpHeaders testHttpHeaders = new HttpHeaders();
    testHttpHeaders.add("test-header-key", "test-header-value");
    final HashMap<String, String> mapHeaders = new HashMap<>();
    testHttpHeaders.forEach((key, value) -> {
        mapHeaders.put(key, value.get(0));
    });
    when(tracer.extract(eq(Format.Builtin.HTTP_HEADERS), ArgumentMatchers.any(TextMapAdapter.class))).thenReturn(testSpanContext);
    io.opentracing.SpanContext resultSpanContext = utilUnderTest.extractParentSpan(testHttpHeaders);
    Assert.assertEquals(resultSpanContext.toTraceId(), traceId.toString());
    Assert.assertEquals(resultSpanContext.toSpanId(), spanId.toString());
}