Also can be pretty handy when there's hardware that needs something very specific to happen to work properly. Mocks can give you (some) confidence that when you

Also can be pretty handy when there's hardware that needs something very specific to happen to work properly. Mocks can give you (some) confidence that when you poke the I2C bus, you won't hang it up. But it's very easy to overdo it and end up testing irrelevant implementation details instead.