JdbcTracingTest.java

    @Test
    public void concurrentParents() {
        IntStream.rangeClosed(1, 150).parallel().forEach(i -> {
            // each iteration is like a request
            try (ActiveSpan parent = tracer.buildSpan("parent_" + i).startActive()) {
                jdbcTemplate.execute("select 1");
            }
        });

        // for each request, we have one extra span, the jdbc one
        assertEquals(300, tracer.finishedSpans().size());

        tracer.finishedSpans()
                .stream()
                .filter((s) -> s.operationName().startsWith("parent_"))
                .forEach(parent -> {
                    // each parent span should have one and only one child
                    assertEquals(1,
                            tracer.finishedSpans()
                                    .stream()
                                    .filter(child -> child.parentId() == parent.context().spanId())
                                    .count()
                    );
                });
    }