foo.java

  @Test
  void testThing(){
    // You probably want to do this in setup?
    OpenTelemetry otel = OpenTelemetrySdk.builder().build();

    SpanBuilder builder = otel.getTracer("foo")
        .spanBuilder("span");
    Span span = builder.startSpan();
    try (Scope scope = span.makeCurrent()) {
      
      { // This would be your method under test
        span.setAttribute("jim", "bob");
      }

      String value = ((SdkSpan) span).toSpanData().getAttributes().get(stringKey("jim"));
      assertThat(value).isEqualTo("bob");
    }
    finally {
      span.end();
    }
  }