A software tester walks into a bar

Runs into a bar.
Crawls into a bar.
Dances into a bar.
Flies into a bar.
Jumps into a bar.

And orders:

a beer.
2 beers.
0 beers.
99999999 beers.
a lizard in a beer glass.
-1 beer.
"qwertyuiop" beers.
Testing complete.

A real customer walks into the bar and asks where the bathroom is.

The bar goes up in flames.

Inevitably whatever is under the glass gets wet anyway... because it's raining.