func TestPrecedence(t *testing.T) {
	t.Setenv("DD_TRACE_AGENT_URL", "unix:///made-up-path-that-does-not-exist")
	received := make(chan struct{}, 1)
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		select {
		case received <- struct{}{}:
		default:
		}
	}))
	defer server.Close()

	err := Start(
		WithAgentAddr(server.Listener.Addr().String()),
		WithPeriod(1*time.Second),
	)
	require.NoError(t, err)
	defer Stop()

	timeout := time.After(5 * time.Second)
	select {
	case <-timeout:
		t.Fatal("should have received a profile already")
	case <-received:
	}
}