def test_add(self):
        prio_set_list = event._PrioritizedSetList()
        objs = [(i,) for i in range(5)]

        prio_set_list.add(0, objs[0])
        assert prio_set_list.list == [(0, {objs[0]})]

        prio_set_list.add(0, objs[1])
        assert prio_set_list.list == [(0, {objs[0], objs[1]})]

        prio_set_list.add(10, objs[2])
        assert prio_set_list.list == [(10, {objs[2]}),
                                      (0,  {objs[0], objs[1]})]

        prio_set_list.add(-10, objs[3])
        assert prio_set_list.list == [( 10, {objs[2]}),           # noqa: E201
                                      (  0, {objs[0], objs[1]}),  # noqa: E201
                                      (-10, {objs[3]})]
        prio_set_list.add(-1, objs[4])
        assert prio_set_list.list == [( 10, {objs[2]}),           # noqa: E201
                                      (  0, {objs[0], objs[1]}),  # noqa: E201
                                      ( -1, {objs[4]}),           # noqa: E201
                                      (-10, {objs[3]})]
def test_mirror_formula():
    u, v, f = symbols('u, v, f')
    assert mirror_formula(focal_length=f, u=u) == f*u/(-f + u)
    assert mirror_formula(focal_length=f, v=v) == f*v/(-f + v)
    assert mirror_formula(u=u, v=v) == u*v/(u + v)
    assert mirror_formula(u=oo, v=v) == v
    assert mirror_formula(u=oo, v=oo) is oo
    assert mirror_formula(focal_length=oo, u=u) == -u
    assert mirror_formula(u=u, v=oo) == u
    assert mirror_formula(focal_length=oo, v=oo) is oo
    assert mirror_formula(focal_length=f, v=oo) == f
    assert mirror_formula(focal_length=oo, v=v) == -v
    assert mirror_formula(focal_length=oo, u=oo) is oo
    assert mirror_formula(focal_length=f, u=oo) == f
    assert mirror_formula(focal_length=oo, u=u) == -u
    raises(ValueError, lambda: mirror_formula(focal_length=f, u=u, v=v))