Mutation testing with Pitest

Inspired by the last JUG Saxony visit, where Sven Ruppert held a talk about mutation testing I wanted to try out this possibility to develop useful test cases with high test coverage.

Compatibility / Runtime Environment

Unfortunately, the PITest plugin does not yet support Java 9 and JUnit 5 natively, so the example has currently following requirements regarding runtime environment :

• Java 8
• JUnit 4.12
• Maven 3.5
• PITest 1.3.*
• AssertJ 3.9.*

Integrate PITest

It is very easy to use PITest.

1. Add the dependency to pom.xml file:

   <dependency>
       <groupId>org.pitest</groupId>
       <artifactId>pitest-parent</artifactId>
       <version>${pitest.version}</version>
       <type>pom</type>
       <scope>test</scope>
   </dependency>

2. Add plugin configuration to pom.mxl file

   <plugin>
       <groupId>org.pitest</groupId>
       <artifactId>pitest-maven</artifactId>
       <version>1.3.2</version>
       <configuration>
           <mutators>
               <mutator>ALL</mutator>
           </mutators>
           <targetClasses>
               <param>it.heber.sandbox.mutationtest.*</param>
           </targetClasses>
           <targetTests>
               <param>it.heber.sandbox.*</param>
           </targetTests>
       </configuration>
   </plugin>

The example above is the simplest. PITest provides various configurations very well described into PITest Maven Quick Start page.

Run PITest

To use pitest, all you have to do is activate the appropriate plugin for Maven projects and start mvn pitest:mutationCoverage after running the test.

PITest results

PITest provides very understandable reports. Together with the line code coverage, it measures the mutation coverage. There are statistics at package level. These reports can be transferred to a reporting server via the building/ test chain and thus made accessible.

Installation and Setup

Following steps are required to install the plugin:

1. Clone this repository to your developer workspace instance as mutation-test project:

   $ git clone https://github.com/UweHeber/mutation-test mutation-test

2. Run following Maven commands:

   • mvn clean install
   • mvn pitest:mutationCoverage

License

This example is licensed under the MIT license. See LICENSE for details.