Problems with syntetic code benchmarks like sonar (with coberture) often link to problematic project configuration. It took me at least few moths to find source of “0% code coverage” problem in one of my sonar projects. Solution was in fact accidental (side effect of project pom clean up) because it was related with wrong plugin configuration / management.
First of all use plugin / dependency management – it will automatically protect you against multi version conflicts (in mentioned project surefire plugin was used in 3 different versions ).
Keep your configuration clean and simple – avoid copy & paste plugin configuration (Why o why did I copy such surfire configuration ??? – i.e. below configuration is not compatible with 2.3 version)