({});
    const scopedId = new tr.model.ScopedId('ptr', '0x1000');
    collection.idWasDeleted(
        scopedId, 'cat', 'cc::LayerImpl', 10);
    const s15 = collection.addSnapshot(
        scopedId, 'cat', 'cc::PictureLayerImpl', 15, {}, 'cc::LayerImpl');
    collection.updateBounds();
    assert.strictEqual(10, collection.bounds.min);
    assert.strictEqual(15, collection.bounds.max);
    assert.strictEqual(s15.objectInstance.name, 'cc::PictureLayerImpl');
  });

  test('autoDelete', function() {
    con