The item of code you have quoted is what is known as an example;

Sure its not; yeah, its in the example directory, but it does a real job , and does it well, and comes with documentation; it is a real useful program

if it were used in a professional environment you would write a unit test for it...

Maybe it is being used in "a real professional environment"? Maybe different environments have different standards? Maybe, there is a threshold, for when to turn stuff into modules, when to write unit tests?