What's not working with this spec? I would put it in a separate it block though and I wouldn't necessarily use the exact value but rather say smaller or use one of the nicer matchers wait a sec... e.g. the be_within matcher [here](https://www.relishapp.com/rspec/rspec-expectations/docs/built-in-matchers) - that could be within a delta of 0.1 * initial size of 0.8 * initial_size