p1+/-p2
= ??
123
654
789
+=-
Checking is not testing

This exercise may help you understand this better.
Try these "Tests" on the Calculator to the above.
Did the calculator give the correct answers?

Could this calculator pass an automated test suite with the prescribed checks?

Good, it works. Right?

Try Testing it for real.
Make observations about strange behaviors.
Try entering math problems not on the list.



These are some of the known/built in issues with the calculator: See if you can find more, please let me know if you do.


The Grand Rapids Testers recently used this as a converstation starter at a meeting, see the Meeting Recap for details. please feel free to do the same. Let us know your results.

For more on the differences between checking and testing please check out what Michael Bolton has to say: http://www.developsense.com/blog/2009/08/testing-vs-checking/

Please email thoughts and comments to dave@hopasaurus.com

Screenshot of C# version


I was looking for something to build with C# and decided to recreate this silly little "Calculator": CheckingIsNotTesting.zip try it out. All the same "Features" of the Javascript version.