Sometimes a gif says more than a thousand words. In this case, what happens when you only focus on unit tests and don’t test anything else?
Here is my personal collection of “X unit tests, 0 integration/usability tests”
The faucet works, the sink works…
The tunnel works, the truck runs…
The trash can works, the dryer works…
And my personal favorite:
The lock works!
The search for simplicity 
I think you also can add this one š
https://makeagif.com/i/X8_Mpz
That’s brilliant! š Thank you!