def METHOD_NAME(self, ot_tracer, test_spans):
    def f():
        with ot_tracer.start_span("f") as span:
            gevent.sleep(0.04)
            span.set_tag("f", "yes")
    def g():
        with ot_tracer.start_span("g") as span:
            gevent.sleep(0.03)
            span.set_tag("g", "yes")
    with ot_tracer.start_active_span("root"):
        gevent.joinall([gevent.spawn(f), gevent.spawn(g)])
    traces = test_spans.pop_traces()
    assert len(traces) == 1
    assert len(traces[0]) == 3