Comment by lloeki

Definitely a useful thing to do to validate UI/UX/fitness.

Relying on blackbox components first mocked then later swapped (or kept for testing) with the real implementation is also a thing, especially when dealing with hardware. It's a bit hard to put moisture sensors on CI!

That said...

I would have recommended at least being open about it being a mockup, but even when doing so I've had customers telling me "so why can't you release this tomorrow since it's basically done!? why is there still two months worth of work, you're trying to rip us off!!!"