Open source bridge testing antipatterns presentation

Testing Antipatterns
Matt Robinson
Puppet Labs

Anti - What?

Antipattern ( Dark Pattern ):
A pattern that is commonly used but is ineffective and/or counterproductive

Who has an extensive test suite?

Who feels like they should test more?

Who dislikes, even dreads, writing tests?

Testing Can Be Fun Text Text Text Text http://xkcd.com/583/

For example:

Red Green TDD Addiction

Testing Framework Games (although these can be a distraction) (although these can be a distraction)

Not looking like an idiot - that’s fun right?

Why Automated Testing?
Prevents regressions
Improves confidence
Documents requirements
Catches errors before codes ships
You fill in the blank _________

Overheard Reasons Not to Test
Don’t trust the tests
Who tests the tests? Quis custodiet ipsos custodes?
Makes refactoring harder
Not enough return on investment (ROI)
Too hard and/or time consuming

Antipatterns that have bitten me the most

Not Running Tests Often Enough

If it’s Hard and Important Do it More Often

testing, deploying, releasing, exercising, meditating, writing, public speaking

How Often?
Before deployment or release
After every commit: CI (Continuous Integration) - Jenkins, Cruise Control, BuildBot, Cerebrus, CI Joe
Before every commit (or push): discipline, git hooks
Every save: autotest, watchr

Not Fixing Broken Tests Before Committing New Code

The Slowpoke

How Slow Is Too Slow?

Unit Test Suite Took 8 Hours to Run - On One Project

Single Test Took 2 Minutes to Start

So slow that rewriting it in PHP would make it faster

How to Get Faster
Make your implementation code faster
Run your tests in parallel
Optimize your tests (new framework, trick garbage collector, rewrite culprits)
Mark some tests as slow and only run them occasionally

The Mockery

Why mock when the real things will do?

Testing at the Wrong Level

unit, smoke, functional, integration, acceptance

Success Against All Odds (test never fails) (test never fails)

Testing Implementation Instead of Behavior

Testing Implementation

Testing Behavior

Order Dependent Failures

You’ve got too much global state

Excessive Setup

What are we testing again?

The Dodger - Never tests desired behavior
The Stranger - Misplaced tests
Local Hero - Worked on my dev box
Generous Leftovers - Fills your hard drive
The Giant - You may have a God object
The Loudmouth - Spams your test logs
Other Antipatterns

Summary

Avoid Antipatterns and Testing Can Be Fun

Links
http://blog.james-carr.org/2006/11/03/tdd-anti-patterns/
http://jasonrudolph.com/blog/testing-anti-patterns-how-to-fail-with-100-test-coverage/
http://blog.rubybestpractices.com/posts/gregory/034-issue-5-testing-antipatterns.html
http://c2.com/cgi/wiki?AntiPatternsCatalog
http://martinfowler.com/articles/mocksArentStubs.html

Open source bridge testing antipatterns presentation

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