What is mutation testing? (I)

[Do you want a spanish version of this page? Follow this link].

Suppose you are the head of a publishing house, and that you need to hire a style and spelling checker. If you have a set of candidates, a possible way for selecting the best one is to give them a text (such as that on the left side, which is the first paragraph of The Catcher in the Ray novel, by J.D. Salinger) with some errors, and then hiring that one who find more typos. 

If you realy want to hear about it, the first thing you'll probably want know is where I was born, an what my lousy child hood was like, and how my parents where occupied and all be fore they had me, and all that David Coperfield kind of crap, but I don't feel like going in it, if you want to know the true.


If we're not in a mistake, there are the following nine typos in it:

If you really want to hear about it, the first thing you'll probably want to know is where I was born, and what my lousy childhood was like, and how my parents were occupied and all before they had me, and all that David Copperfield kind of crap, but I don't feel like going into it, if you want to know the truth.

When mutation was proposed more than 30 years ago, the basic idea behind it was the same: to evaluate the quality of test suites as a function of the number of faults detected by the cases in the test suite, when are executed against the SUT. As more faults are detected, higher is the test suite quality.

As well as we have "injected" artificial typos in the original Salinger's text, mutation relies on the insertion of artificial faults in the code of the system under test (the SUT). These artificial faults are inserted by means of "mutation operators", which introduce some kind of syntactic change in the SUT.

In next chapter we'll talk about mutation operators :)

New version

A new version of Bacterio has been released:

http://www.alarcosqualitycenter.com/index.php/news?Itemid=93

News

[FEBRUARY 2012] New version BACTERIO Mutation Test System   Alarcos Quality Center has developed with Alarcos Research Group a new versión of the tool (BACTERIO Mutation Test System) with the follow features: Exploratory testing automation. "Mutant schema" implemented. Some types of mutation. Execution time storage. Parallel execution. Equivalent mutants detection assistance. You can download a demo version here.

Bacterio, free for students, professors and university researchers

Bacterio is a Java desktop-based tool for mutation testing. It is very easy to use and implements most of the techniques proposed in literature (bytecode mutation, mutant sampling, mutant schemata, parallel execution, n-order mutation, strong and weak mutation, etc.).
It is specially suitable for doing mutation at system and integration levels.
Besides strong and weak, it implements a novel comparison method called Flexible Weak Mutation.

• If you work or study in a university, feel free to write us and request a complete version.
• Otherwise, ask for a demo to Alarcos Quality Center.