AspectJMaven/cobertura

You can use Cobertura to check test coverage of a project built with Maven and AspectJ.

In the following POM file, we used Cobertura in combination with the AspectJ Maven Plugin :

<project>
    [...]
        <build>
                <plugins>
                        <!-- Configure the ApsectJ Maven Plugin -->
                        <plugin>
                                <groupId>org.codehaus.mojo</groupId>
                                <artifactId>aspectj-maven-plugin</artifactId>
                                <executions>
                                        <execution>
                                                <goals>
                                                        <goal>compile</goal>
                                                        <goal>test-compile</goal>
                                                </goals>
                                        </execution>
                                </executions>
                                <configuration>
                                        <source>1.5</source>
                                        <target>1.5</target>
                                </configuration>
                        </plugin>
                </plugins>
        </build>
        <reporting>
                <plugins>
                        <!-- This is the standard reporting plugin -->
                        <plugin>
                                <artifactId>maven-project-info-reports-plugin</artifactId>
                        </plugin>
                        <!-- This is the Cobertura reporting plugin -->
                        <plugin>
                                <groupId>org.codehaus.mojo</groupId>
                                <artifactId>cobertura-maven-plugin</artifactId>
                        </plugin>
                </plugins>
        </reporting>
        <dependencies>
                <dependency>
                        <groupId>junit</groupId>
                        <artifactId>junit</artifactId>
                        <version>4.7</version>
                        <scope>test</scope>
                </dependency>
                <dependency>
                        <groupId>org.aspectj</groupId>
                        <artifactId>aspectjrt</artifactId>
                        <version>1.6.6</version>
                </dependency>
        </dependencies>

</project>

Now, launching the maven site goal :

mvn clean site

Will in turn :

• Clean
• Build files found in src/main/java using AspectJ (including .aj aspects)
• Build files found in src/test/java using AspectJ (including .aj aspects used only during tests)
• Instrument with Cobertura the main classes AND aspects
• Run the tests using Cobertura instrumentation
• Collects Cobertura instrumentation results
• Build the HTML site including the "Cobertura Coverage Report".

Cobertura will correctly instrument also aspects, however a few minor problems arise :

• since AspectJ inlines a few calls inside methods using "line 1" of the target class file, or the first line of the method, you'll see cobertura reporting a lot of hits on this lines, even if they does not contain any apparently useful code.
• since AspectJ places a few calls to obtain aspect instances, and a few checks, you'll see Cobertura giving a "red marker" indicating that at a certain line there have been partial code execution, while in fact it is not possible looking at the java code, unless you know that AspectJ is placing an "if" there.