Unit Testing: Mandatory or Optional?

I recently came across this nice post (http://agilewarrior.wordpress.com/2012/10/06/its-not-about-the-unit-tests/) and I wanted to share it with you, as it carries a very important message that separates the capable Software Engineers from the great Software Engineers.

In our industry, when we come across a practice that helps us to improve we tend to shout about it and over state its impact. In this post the author points out that Unit Testing is not commonly used in iPhone and iPad development; and yet their software is often highly regarded anyway. As an individual who was taught that high quality software had to be unit tested, this was earth shattering news for him; it literally led to many sleepless nights while he wrestled to incorporate this observation into his view of the world. Needless to say, unit testing is a very powerful tool and that it does belong in every professional software engineers tool box. But knowing when to use it, when not to use it and how to get the best gains from it is important. In fact, like any tool, misusing it can be just as bad as not using it at all. And most of all, unit testing is not a substitute for caring about the product that we are crafting.

Test tip with Maven Surefire

When starting a new Maven module, I strongly encourage everybody to set the unit tests to execute in parallel.

There are a few benefits to this:

• most obviously the unit tests run faster on modern multi-cpu boxes
• it helps to tease out concurrent bugs earlier
• it helps to enforce good unit testing practices; specifically that there should be no side effects between tests and the order of test execution should not matter
• enabling this feature later on in a project is possible, but it is nearly always a pain so start it early and you will get its benefits almost for free

I recently introduced this practice to a new team that I am working with and upon enabling it on a recent module whose unit tests were already in a good state it highlighted a concurrency bug in a third party library that was being pulled in that had not yet been detected. Who would have guessed it? Early detection of problems is awesome.

To enable in Maven just add the following runes to you pom.xml file:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <configuration>
        <parallel>methods</parallel>
        <threadCount>2</threadCount>
    </configuration>
</plugin>