So it's probably best to consider it for unit and "small scale" aggregated functional testing then? This is actually the first time I've come across it. It seem

So it's probably best to consider it for unit and "small scale" aggregated functional testing then? This is actually the first time I've come across it. It seems like it would be good to consider it for new projects or new features but would be quite an ask to retrofit it on legacy code that wasn't already well "unit tested"?