On the screen you sent the main content root is something like '/home/cerdic/projects.....'
and the tests are located in is '/opt/cerdic....'
On account of this tests was attached as secondary content root.

If you want them to be under main content root you must place them under it

I guess you misunderstood the problem(side effect of symlink) : I created the project from a POM file, and those pom files never ever specify any absolute path. My POM was analyzed by IJ and so created the modules by itself. My project looks like this :

pom.xml : project
fulty-core/pom.xml : module 1
fulty-core/src/main : main sources
fulty-core/src/tests : test sources
fulty-core/src/tests/java : detected as new content root instead of test sources

fulty-web/pom.xml : module 2
fulty-web/src/main : main sources
fulty-web/src/tests : test sources
fulty-web/src/tests/java : detected as new content root instead of test sources

The fact that you read /opt/CEDRIC in the content root is IMHO a side effect that I symlinked my /home/cedric/PROJECTS directory to /opt/CEDRIC/PROJECTS. In insist that this problem did not occur in M2, so there must be something wrong. With 7 finale, I am forced to remove the content root then set the test sources for each module each time I restart IJ.

Ok, that certainly the bug with symbolic links. Thanks for clarification