Unit testing Anti-patterns catalogue

Question

anti-pattern : there must be at least two key elements present to formally distinguish an actual anti-pattern from a simple bad habit, bad practice, or bad idea:

• Some repeated pattern of action, process or structure that initially appears to be beneficial, but ultimately produces more bad consequences than beneficial results, and
• A refactored solution that is clearly documented, proven in actual practice and repeatable.

Vote for the TDD anti-pattern that you have seen "in the wild" one time too many.
The blog post by James Carr and Related discussion on testdrivendevelopment yahoogroup

If you've found an 'unnamed' one.. post 'em too. One post per anti-pattern please to make the votes count for something.

My vested interest is to find the top-n subset so that I can discuss 'em in a lunchbox meet in the near future.

Answer 1

The Butterfly

You have to test something which contains data that changes all the time, like a structure which contains the current date, and there is no way to nail the result down to a fixed value. The ugly part is that you don't care about this value at all. It just makes your test more complicated without adding any value.

The bat of its wing can cause a hurricane on the other side of the world. -- Edward Lorenz, The Butterfly Effect

Answer 2

Wait and See

A test that runs some set up code and then needs to 'wait' a specific amount of time before it can 'see' if the code under test functioned as expected. A testMethod that uses Thread.sleep() or equivalent is most certainly a "Wait and See" test.

Typically, you may see this if the test is testing code which generates an event external to the system such as an email, an http request or writes a file to disk.

Such a test may also be a Local Hero since it will FAIL when run on a slower box or an overloaded CI server.

The Wait and See anti-pattern is not to be confused with The Sleeper.

Answer 3

The Free Ride / Piggyback -- James Carr, Tim Ottinger
Rather than write a new test case method to test another/distinct feature/functionality, a new assertion (and its corresponding actions i.e. Act steps from AAA) rides along in an existing test case.

Answer 4

The Slow Poke

A unit test that runs incredibly slow. When developers kick it off, they have time to go to the bathroom, grab a smoke, or worse, kick the test off before they go home at the end of the day. (Src: James Carr's post)

a.k.a. the tests that won't get run as frequently as they should

Answer 5

The Turing Test

A testcase automagically generated by some expensive tool that has many, many asserts gleaned from the class under test using some too-clever-by-half data flow analysis. Lulls developers into a false sense of confidence that their code is well tested, absolving them from the responsibility of designing and maintaining high quality tests. If the machine can write the tests for you, why can't it pull its finger out and write the app itself!

Hello stupid. -- World's smartest computer to new apprentice (from an old Amiga comic).

Answer 6

Excessive Setup -- James Carr
A test that requires a huge setup in order to even begin testing. Sometimes several hundred lines of code are used to prepare the environment for one test, with several objects involved, which can make it difficult to really ascertain what is tested due to the “noise” of all of the setup going on. (Src: James Carr's post)