There are two different ways to feed Sonar with information on unit tests execution and code coverage:

• Using its embedded engine to let Sonar directly launch the unit tests execution and code coverage. Then, the analyzer will automatically fed the database with data exported from the generated reports.
• Reusing existing reports that have been previously generated by external tools.

Project samples covering the different cases below are available on github that can be browsed or downloaded: projects/code-coverage/

Using Sonar Embedded Engine

Maven supports this mode with the following code coverage tools: JaCoCo, Cobertura, Emma and Clover.

The Sonar Ant Task and the Sonar Runner do not support this mode.

Compile Before running a Sonar analysis with JaCoCo set as the code coverage tool, the source code has to be compiled.

First, tell Sonar to execute the unit tests and the code coverage tool:

With Maven in your pom file:

Maven Project

With Maven, then, you just have to tell Sonar which code coverage engine you wish to use: jacoco or cobertura or emma or clover.

Note that this property can be set at Sonar instance level through the web interface: Settings > Configuration > General Settings > Java.

Sample projects are available on github that can be browsed or downloaded:

• Maven and JaCoCo: projects/code-coverage/ut/maven/ut-maven-jacoco-runTests
• Maven and Cobertura: projects/code-coverage/ut/maven/ut-maven-cobertura-runTests
• Maven and Emma: projects/code-coverage/ut/maven/ut-maven-emma-runTests

Maven Multi-module Project and JaCoCo

For multi-module Maven projects, compute overall code coverage by unit tests across modules. This case clearly lies between unit tests and integration tests but this is widely used.

Sample projects are available on github that can be browsed or downloaded: projects/code-coverage/combined ut-it/maven/combined-ut-it-multimodule-maven-jacoco

Note that this project structure is not compatible with the below feature: mapping of unit tests and covered code.

Mapping of Unit Tests and Covered Code

Since Sonar 3.5, it is possible to display the mapping of unit tests and covered code. The objective is to answer the following questions:

• Which files are covered by a given unit test?
• How many lines of code are covered by a given unit test?
• Which lines are covered by a given unit test?
• Which tests do cover a given line of code?

This use case can only be achieved with Maven and JaCoCo for now.

A sample project is available on github that can be browsed or downloaded: projects/code-coverage/ut/maven/ut-maven-jacoco-runTests. What is necessary to get this mapping is contained between 'BEGIN/END: Specific to mapping unit tests and covered code' tags in the pom file. Note that you have to run the analysis with the 'coverage-per-test' profile. Read the README file for more information.

Reusing Existing Reports

Every analyzer supports this reusing reports mode.

To be reused by Sonar:

• The tests execution reports have to comply to the JUnit XML format.
• The code coverage reports have to be generated by either JaCoCo, Emma, Cobertura or Clover.

First, tell Sonar to reuse existing reports:

With Maven in your pom.xml file:

With Ant in your build.xml file:

With Sonar Runner in your sonar-project.properties file:

Test Execution Reports

Tell Sonar where your unit tests execution reports are: absolute or relative path to the directory containing your reports

With Maven in your pom file:

With Ant in your build file:

With Sonar Runner in your sonar-project file:

Code Coverage Report 

First, tell Sonar which code coverage engine has been used to generate the reports: jacoco or cobertura or emma or clover.

Then, tell Sonar where to get the code coverage reports:

With Ant in your build file:

With Sonar Runner in your sonar-project file:

Depending on the code coverage tool you used to generate your report, replace jacoco by emma, cobertura or clover in the property name.

Blog

See also the Manage Code Coverage by Unit Tests with Sonar blog post.

FAQ

0% code coverage reported whereas unit tests are correctly executed

This problem occurs while using the Maven Cobertura Plugin and a special configuration of the Maven Surefire Plugin preventing unit tests to be forked. This problem can be solved by removing the line "<forkMode>never</forkMode>" in the Maven configuration file (see SONAR-1445 and MCOBERTURA-70).