This is that, and the exact same vibe, except: it promises to keep being that simple even after you add threads, and locks, and network calls, and disk accesses and..

With this, if you write a test for a function that makes a network call and writes the result to disk, your test will fail if your code does not handle the network call failing or stalling indefinitely, or the disk running out of space, or the power going out just before you close the file, or..

So it’s; yes, but it expands the space where testing is as easy as unit testing to cover much more interesting levels of complexity