@Ninir: After thinking about that, I think it will better to use a dedicated script to launch all tests. We have to following elements to check:
* Bash functions
* Python modules and functions
* Installer / Uninstaller
*  When CR is installed on the virtual machine: testing if the web part is working well / testing if binary script works ("centralreport stop", "centralreport restart" etc.)

According to the Travis documentation, we can't use more than one script in the "script" part (in .travis.yml).

To being cleaner, we can create a "tests" directory in the bash part, and another in the python part.
Each script will test one script/module (http://docs.python.org/2/library/unittest.html). And we can have a "global" script which launches all "sub" scripts. Travis just launches the "global" bash and the global python scripts.